diff --git a/rsbuild.config.ts b/rsbuild.config.ts
index 9aef989..8905636 100644
--- a/rsbuild.config.ts
+++ b/rsbuild.config.ts
@@ -98,4 +98,4 @@ const config: ReturnType<typeof defineConfig> = defineConfig(({ envMode }) => {
   }
 })
 
-export default config
\ No newline at end of file
+export default config
diff --git a/src/index.css b/src/index.css
index 6b09e2f..fcb8334 100644
--- a/src/index.css
+++ b/src/index.css
@@ -16,14 +16,6 @@ body {
   overflow: auto;
   border: 1px solid rgba(148, 163, 184, 0.24);
   border-radius: 8px;
-  background:
-    linear-gradient(rgba(148, 163, 184, 0.08) 1px, transparent 1px),
-    linear-gradient(90deg, rgba(148, 163, 184, 0.08) 1px, transparent 1px),
-    linear-gradient(135deg, #ffffff 0%, #f8fafc 52%, #eef6ff 100%);
-  background-size:
-    24px 24px,
-    24px 24px,
-    auto;
 }
 
 .oj-mermaid-surface > svg {
diff --git a/src/oj/problem/components/SubmitFlowchart.vue b/src/oj/problem/components/SubmitFlowchart.vue
index f407dc6..cc0b4f8 100644
--- a/src/oj/problem/components/SubmitFlowchart.vue
+++ b/src/oj/problem/components/SubmitFlowchart.vue
@@ -69,8 +69,6 @@ const page = ref(1)
 // ==================== WebSocket 相关函数 ====================
 // 处理 WebSocket 消息
 const handleWebSocketMessage = (data: FlowchartEvaluationUpdate) => {
-  console.log("收到流程图评分更新:", data)
-
   if (data.type === "flowchart_evaluation_completed") {
     loading.value = false
     latestRating.value = {
@@ -79,11 +77,8 @@ const handleWebSocketMessage = (data: FlowchartEvaluationUpdate) => {
     }
     message.success(`流程图评分完成！得分: ${data.score}分 (${data.grade}级)`)
   } else if (data.type === "flowchart_evaluation_failed") {
-    console.log("处理评分失败消息")
     loading.value = false
     message.error(`流程图评分失败: ${data.error}`)
-  } else {
-    console.log("未知的消息类型:", data.type)
   }
 }
 
@@ -94,7 +89,6 @@ const { connect, disconnect, subscribe } = useFlowchartWebSocket(
 
 // 订阅提交更新
 function subscribeToSubmission(submissionId: string) {
-  console.log("开始订阅WebSocket更新")
   subscribe(submissionId)
 }
 
@@ -287,16 +281,14 @@ onUnmounted(() => {
       <n-grid :cols="5" :x-gap="16">
         <!-- 左侧：流程图预览区域 -->
         <n-gi :span="3">
-          <n-card title="流程图预览">
-            <div class="flowchart">
-              <n-spin :show="rendering">
-                <n-alert v-if="renderError" type="error" title="流程图渲染失败">
-                  {{ renderError }}
-                </n-alert>
-                <div class="flowchart" v-else ref="mermaidContainer"></div>
-              </n-spin>
-            </div>
-          </n-card>
+          <div class="flowchart">
+            <n-spin :show="rendering">
+              <n-alert v-if="renderError" type="error" title="流程图渲染失败">
+                {{ renderError }}
+              </n-alert>
+              <div class="flowchart" v-else ref="mermaidContainer"></div>
+            </n-spin>
+          </div>
           <!-- 加载到编辑器按钮 -->
           <n-flex style="margin-top: 16px" justify="center">
             <n-button @click="loadToEditor" type="primary">
diff --git a/src/oj/submission/components/FlowchartLink.vue b/src/oj/submission/components/FlowchartLink.vue
index 6706e8f..34a1cdb 100644
--- a/src/oj/submission/components/FlowchartLink.vue
+++ b/src/oj/submission/components/FlowchartLink.vue
@@ -1,5 +1,5 @@
 <template>
-  <n-button v-if="showLink" type="info" text @click="goto">
+  <n-button v-if="showLink" type="info" text @click="handleClick">
     {{ flowchart.id.slice(0, 12) }}
   </n-button>
   <n-text v-else class="flowchart-id" @click="handleClick">
@@ -7,8 +7,8 @@
   </n-text>
 </template>
 <script setup lang="ts">
+import type { FlowchartSubmissionListItem } from "utils/types"
 import { useUserStore } from "shared/store/user"
-import { FlowchartSubmissionListItem } from "utils/types"
 
 const userStore = useUserStore()
 
@@ -27,10 +27,6 @@ const showLink = computed(() => {
   return props.flowchart.username === userStore.user?.username
 })
 
-function goto() {
-  emit("showDetail", props.flowchart.id)
-}
-
 function handleClick() {
   emit("showDetail", props.flowchart.id)
 }
diff --git a/src/shared/components/FlowchartEditor/CustomNode.vue b/src/shared/components/FlowchartEditor/CustomNode.vue
index 71e6b2a..6795875 100644
--- a/src/shared/components/FlowchartEditor/CustomNode.vue
+++ b/src/shared/components/FlowchartEditor/CustomNode.vue
@@ -4,7 +4,7 @@
     :class="{ 'is-hovered': isHovered, 'is-editing': isEditing }"
     :data-node-type="nodeType"
     :draggable="!isEditing"
-    @mouseenter="isHovered = true"
+    @mouseenter="handleMouseEnter"
     @mouseleave="handleMouseLeave"
     @dblclick="handleDoubleClick"
     @dragstart="handleDragStart"
@@ -53,11 +53,17 @@ import { getNodeTypeConfig } from "./useNodeStyles"
 import NodeHandles from "./NodeHandles.vue"
 import NodeActions from "./NodeActions.vue"
 
-// 类型定义
+interface NodeData {
+  label: string
+  color: string
+  originalType: string
+  customLabel?: string
+}
+
 interface Props {
   id: string
   type: string
-  data: any
+  data: NodeData
 }
 
 interface Emits {
@@ -147,6 +153,7 @@ const handleCancelEdit = () => {
 }
 
 const handleMouseEnter = () => {
+  isHovered.value = true
   if (hideTimeout) {
     clearTimeout(hideTimeout)
     hideTimeout = null
diff --git a/src/shared/components/FlowchartEditor/Toolbar.vue b/src/shared/components/FlowchartEditor/Toolbar.vue
index fe296c4..df95c7e 100644
--- a/src/shared/components/FlowchartEditor/Toolbar.vue
+++ b/src/shared/components/FlowchartEditor/Toolbar.vue
@@ -1,6 +1,7 @@
 <script setup lang="ts">
 import { computed } from "vue"
 import { getNodeTypeConfig } from "./useNodeStyles"
+import { currentDragNodeType } from "./useDnD"
 
 // 拖拽开始处理
 const onDragStart = (event: DragEvent, type: string) => {
@@ -8,6 +9,17 @@ const onDragStart = (event: DragEvent, type: string) => {
 
   event.dataTransfer.setData("application/vueflow", type)
   event.dataTransfer.effectAllowed = "move"
+  currentDragNodeType.value = type
+
+  // 隐藏浏览器默认拖影，改用 canvas 跟随预览
+  const emptyImg = new Image(1, 1)
+  emptyImg.src =
+    "data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7"
+  event.dataTransfer.setDragImage(emptyImg, 0, 0)
+}
+
+const onDragEnd = () => {
+  currentDragNodeType.value = null
 }
 
 // Props
@@ -42,8 +54,7 @@ const nodeTypes = computed(() =>
   ),
 )
 
-// 获取保存状态标题
-const getSaveStatusTitle = () => {
+const saveStatusTitle = computed(() => {
   if (props.isSaving) {
     return "正在保存..."
   } else if (props.hasUnsavedChanges) {
@@ -53,7 +64,7 @@ const getSaveStatusTitle = () => {
   } else {
     return "已保存"
   }
-}
+})
 </script>
 <template>
   <div class="toolbar">
@@ -68,7 +79,7 @@ const getSaveStatusTitle = () => {
             unsaved: props.hasUnsavedChanges && !props.isSaving,
             saved: !props.hasUnsavedChanges && !props.isSaving,
           }"
-          :title="getSaveStatusTitle()"
+          :title="saveStatusTitle"
         >
           <span v-if="props.isSaving" class="spinner">⏳</span>
           <span v-else-if="props.hasUnsavedChanges">●</span>
@@ -86,6 +97,7 @@ const getSaveStatusTitle = () => {
         class="node-item"
         :draggable="true"
         @dragstart="onDragStart($event, nodeType.type)"
+        @dragend="onDragEnd"
         :style="{ borderColor: nodeType.color }"
         :title="`${nodeType.label} - ${nodeType.description}`"
       >
diff --git a/src/shared/components/FlowchartEditor/index.vue b/src/shared/components/FlowchartEditor/index.vue
index 0b7bf60..90acce5 100644
--- a/src/shared/components/FlowchartEditor/index.vue
+++ b/src/shared/components/FlowchartEditor/index.vue
@@ -14,7 +14,8 @@ import {
 import { Controls } from "@vue-flow/controls"
 import { Background } from "@vue-flow/background"
 
-import { useDnD } from "./useDnD"
+import { useDnD, currentDragNodeType } from "./useDnD"
+import { getNodeTypeConfig } from "./useNodeStyles"
 import { useHistory } from "./useHistory"
 import { useFlowOperations } from "./useFlowOperations"
 import { useCache } from "./useCache"
@@ -42,17 +43,35 @@ const { canUndo, canRedo, saveState, undo, redo } = useHistory()
 const problemStore = useProblemStore()
 const { problem } = storeToRefs(problemStore)
 // 缓存管理
-const { isSaving, lastSaved, hasUnsavedChanges, loadFromCache, clearCache } =
-  useCache(
-    nodes,
-    edges,
-    problem.value?._id
-      ? `flowchart-editor-data-problem-${problem.value!._id}`
-      : "flowchart-editor-data",
-  )
+const {
+  isSaving,
+  lastSaved,
+  hasUnsavedChanges,
+  saveToCache,
+  loadFromCache,
+  clearCache,
+} = useCache(
+  nodes,
+  edges,
+  problem.value?._id
+    ? `flowchart-editor-data-problem-${problem.value!._id}`
+    : "flowchart-editor-data",
+)
 
 // 拖拽处理
-const { onDragOver, onDragLeave, onDrop } = useDnD()
+const { onDragOver, onDragLeave, onDrop, isDragOver, screenDragPos } = useDnD()
+
+const dragPreviewStyle = computed(() => {
+  if (!screenDragPos.value || !currentDragNodeType.value) return null
+  const config = getNodeTypeConfig(currentDragNodeType.value)
+  const type = currentDragNodeType.value
+  return {
+    left: `${screenDragPos.value.x}px`,
+    top: `${screenDragPos.value.y}px`,
+    background: config.color,
+    borderRadius: type === "start" || type === "end" ? "20px" : "8px",
+  }
+})
 
 // 流程操作
 const {
@@ -93,16 +112,18 @@ const handleDrop = (event: DragEvent) => {
 const handleUndo = () => {
   const state = undo()
   if (state) {
-    nodes.value = [...state.nodes]
-    edges.value = [...state.edges]
+    nodes.value = state.nodes
+    edges.value = state.edges
+    saveToCache()
   }
 }
 
 const handleRedo = () => {
   const state = redo()
   if (state) {
-    nodes.value = [...state.nodes]
-    edges.value = [...state.edges]
+    nodes.value = state.nodes
+    edges.value = state.edges
+    saveToCache()
   }
 }
 
@@ -182,6 +203,19 @@ defineExpose({
 
 <template>
   <div class="container" :style="{ height }">
+    <!-- 拖拽时跟随鼠标的节点预览 -->
+    <Transition name="drag-preview">
+      <div
+        v-if="isDragOver && dragPreviewStyle && currentDragNodeType"
+        class="drag-node-preview"
+        :style="dragPreviewStyle"
+      >
+        <span class="preview-icon">{{
+          getNodeTypeConfig(currentDragNodeType).icon
+        }}</span>
+        <span>{{ getNodeTypeConfig(currentDragNodeType).label }}</span>
+      </div>
+    </Transition>
     <VueFlow
       v-model:nodes="nodes"
       v-model:edges="edges"
@@ -191,7 +225,7 @@ defineExpose({
       @connect="handleConnect"
       @edge-click="handleEdgeClick"
       :default-edge-options="{
-        type: 'step',
+        type: 'default',
         style: {
           stroke: '#6366f1',
           strokeWidth: 2.5,
@@ -269,4 +303,36 @@ defineExpose({
   height: 100%;
   position: relative;
 }
+
+.drag-node-preview {
+  position: fixed;
+  transform: translate(-50%, -50%);
+  pointer-events: none;
+  z-index: 9999;
+  padding: 8px 18px;
+  color: white;
+  font-size: 14px;
+  font-weight: 500;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  opacity: 0.55;
+  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
+  white-space: nowrap;
+  border: 2px dashed rgba(255, 255, 255, 0.6);
+  user-select: none;
+}
+
+.preview-icon {
+  font-size: 16px;
+}
+
+.drag-preview-enter-active,
+.drag-preview-leave-active {
+  transition: opacity 0.1s ease;
+}
+.drag-preview-enter-from,
+.drag-preview-leave-to {
+  opacity: 0;
+}
 </style>
diff --git a/src/shared/components/FlowchartEditor/useDnD.ts b/src/shared/components/FlowchartEditor/useDnD.ts
index f894f24..da6b761 100644
--- a/src/shared/components/FlowchartEditor/useDnD.ts
+++ b/src/shared/components/FlowchartEditor/useDnD.ts
@@ -7,28 +7,36 @@ import {
 } from "./useNodeStyles"
 import { getRandomId } from "utils/functions"
 
+// 模块级共享：当前拖拽的节点类型（Toolbar 写入，canvas 读取）
+export const currentDragNodeType = ref<string | null>(null)
+
 /**
  * 简化的拖拽处理
  */
 export function useDnD() {
   const { addNodes, screenToFlowCoordinate } = useVueFlow()
   const isDragOver = ref(false)
+  const screenDragPos = ref<{ x: number; y: number } | null>(null)
 
   // 拖拽悬停处理
   const onDragOver = (event: DragEvent) => {
     event.preventDefault()
     isDragOver.value = true
+    screenDragPos.value = { x: event.clientX, y: event.clientY }
   }
 
   // 拖拽离开处理
   const onDragLeave = () => {
     isDragOver.value = false
+    screenDragPos.value = null
   }
 
   // 拖拽放置处理
   const onDrop = (event: DragEvent) => {
     event.preventDefault()
     isDragOver.value = false
+    screenDragPos.value = null
+    currentDragNodeType.value = null
 
     const type = event.dataTransfer?.getData("application/vueflow")
     if (!type) return
@@ -68,6 +76,7 @@ export function useDnD() {
 
   return {
     isDragOver,
+    screenDragPos,
     onDragOver,
     onDragLeave,
     onDrop,
diff --git a/src/shared/components/FlowchartEditor/useFlowOperations.ts b/src/shared/components/FlowchartEditor/useFlowOperations.ts
index 31abea2..6d6ad50 100644
--- a/src/shared/components/FlowchartEditor/useFlowOperations.ts
+++ b/src/shared/components/FlowchartEditor/useFlowOperations.ts
@@ -1,5 +1,5 @@
 import type { Ref } from "vue"
-import type { Node, Edge } from "@vue-flow/core"
+import type { Node, Edge, Connection } from "@vue-flow/core"
 import { getRandomId } from "utils/functions"
 
 export function useFlowOperations(
@@ -11,12 +11,11 @@ export function useFlowOperations(
   removeEdges: (edgeIds: string[]) => void,
   saveState: (nodes: Node[], edges: Edge[]) => void,
 ) {
-  // 根据节点类型和handle自动推断标签
   const getAutoLabel = (
-    sourceNode: any,
-    targetNode: any,
-    sourceHandle: string,
-    targetHandle: string,
+    sourceNode: Node | undefined,
+    targetNode: Node | undefined,
+    sourceHandle: string | null | undefined,
+    targetHandle: string | null | undefined,
   ) => {
     const sourceType = sourceNode?.data?.originalType || sourceNode?.type
     const targetType = targetNode?.data?.originalType || targetNode?.type
@@ -51,9 +50,7 @@ export function useFlowOperations(
     return ""
   }
 
-  // 连接处理
-  const handleConnect = (params: any) => {
-    // 获取源节点和目标节点
+  const handleConnect = (params: Connection) => {
     const sourceNode = nodes.value.find((node) => node.id === params.source)
     const targetNode = nodes.value.find((node) => node.id === params.target)
 
@@ -79,9 +76,8 @@ export function useFlowOperations(
     saveState(nodes.value, edges.value)
   }
 
-  // 边点击处理 - 单击删除
-  const handleEdgeClick = (event: any) => {
-    removeEdges([event.edge.id])
+  const handleEdgeClick = ({ edge }: { edge: Edge }) => {
+    removeEdges([edge.id])
     saveState(nodes.value, edges.value)
   }
 
@@ -115,12 +111,7 @@ export function useFlowOperations(
         },
       }
 
-      // 使用 Vue Flow 的更新方法
       nodes.value[nodeIndex] = updatedNode
-
-      // 强制触发响应式更新
-      nodes.value = [...nodes.value]
-
       saveState(nodes.value, edges.value)
     }
   }
diff --git a/src/shared/components/FlowchartEditor/useHistory.ts b/src/shared/components/FlowchartEditor/useHistory.ts
index c166234..8ec9a50 100644
--- a/src/shared/components/FlowchartEditor/useHistory.ts
+++ b/src/shared/components/FlowchartEditor/useHistory.ts
@@ -1,11 +1,11 @@
-import { ref, computed } from "vue"
+import { shallowRef, computed } from "vue"
 import type { Node, Edge } from "@vue-flow/core"
 
 /**
  * 简化的历史记录管理
  */
 export function useHistory() {
-  const history = ref<{ nodes: Node[]; edges: Edge[] }[]>([])
+  const history = shallowRef<{ nodes: Node[]; edges: Edge[] }[]>([])
   const historyIndex = ref(-1)
 
   // 是否可以撤销
@@ -14,21 +14,30 @@ export function useHistory() {
   // 是否可以重做
   const canRedo = computed(() => historyIndex.value < history.value.length - 1)
 
+  const deepCopyState = (
+    nodes: Node[],
+    edges: Edge[],
+  ): { nodes: Node[]; edges: Edge[] } =>
+    JSON.parse(JSON.stringify({ nodes, edges })) as {
+      nodes: Node[]
+      edges: Edge[]
+    }
+
   // 保存状态到历史记录
   const saveState = (nodes: Node[], edges: Edge[]) => {
-    const currentState = { nodes: [...nodes], edges: [...edges] }
+    const currentState = deepCopyState(nodes, edges)
 
     // 如果当前不在历史记录的末尾，删除后面的记录
     if (historyIndex.value < history.value.length - 1) {
       history.value = history.value.slice(0, historyIndex.value + 1)
     }
 
-    history.value.push(currentState)
+    history.value = [...history.value, currentState]
     historyIndex.value = history.value.length - 1
 
     // 限制历史记录数量
     if (history.value.length > 20) {
-      history.value.shift()
+      history.value = history.value.slice(1)
       historyIndex.value--
     }
   }
@@ -38,7 +47,7 @@ export function useHistory() {
     if (canUndo.value) {
       historyIndex.value--
       const state = history.value[historyIndex.value]
-      return state
+      return deepCopyState(state.nodes, state.edges)
     }
     return null
   }
@@ -48,7 +57,7 @@ export function useHistory() {
     if (canRedo.value) {
       historyIndex.value++
       const state = history.value[historyIndex.value]
-      return state
+      return deepCopyState(state.nodes, state.edges)
     }
     return null
   }