diff --git a/src/core/manager/EntityManager.ts b/src/core/manager/EntityManager.ts
index cf8f008..79822da 100644
--- a/src/core/manager/EntityManager.ts
+++ b/src/core/manager/EntityManager.ts
@@ -4,6 +4,34 @@ import type BaseRenderer from '@/core/base/BaseRenderer'
 import { getRenderer } from './ModuleManager'
 import { getLineId, parseLineId } from '@/core/ModelUtils'
 
+export class Relation {
+  center = new Set<string>()
+  input = new Set<string>()
+  output = new Set<string>()
+
+  add(type: LinkType, id: string) {
+    if (type === 'in')
+      return this.input.add(id)
+    else if (type === 'out')
+      return this.output.add(id)
+    else if (type === 'center')
+      return this.center.add(id)
+    else
+      throw new Error(`Unknown link type: ${type}`)
+  }
+
+  delete(type: LinkType, id: string) {
+    if (type === 'in')
+      return this.input.delete(id)
+    else if (type === 'out')
+      return this.output.delete(id)
+    else if (type === 'center')
+      return this.center.delete(id)
+    else
+      throw new Error(`Unknown link type: ${type}`)
+  }
+}
+
 /**
  * 实体管理器
  * 缓存所有 数据(ItemJson)和他们的关系, 以及渲染对象 THREE.Object3D
@@ -112,11 +140,28 @@ export default class EntityManager {
 
     option.originEntity = _.cloneDeep(entity)
 
-    this.entities.delete(id)
-    this.removeRelations(id)
+    // 先生成线差量，再清理关系
+    this.generateLineDiffsForDelete(id)
+    this.removeRelations(id)      // 清理关系
+    this.entities.delete(id)      // 删除实体
+
     this.getDiffRenderer(entity.t).deletePoint(id, option)
   }
 
+  generateLineDiffsForDelete(id: string): void {
+    const relations = this.relationIndex.get(id)
+    if (!relations) return
+
+    const removeLine = (relatedId: string, type: LinkType) => {
+      const lineId = getLineId(id, relatedId, type)
+      this.lineDiffs.delete.set(lineId, { startId: id, endId: relatedId, type })
+    }
+
+    relations.center.forEach(relatedId => removeLine(relatedId, 'center'))
+    relations.input.forEach(relatedId => removeLine(relatedId, 'in'))
+    relations.output.forEach(relatedId => removeLine(relatedId, 'out'))
+  }
+
   /**
    * 批量更新结束, 结束后会触发视窗的渲染
    *  这个方法最重要的是进行连线逻辑的处理
@@ -127,9 +172,17 @@ export default class EntityManager {
    */
   endEntityUpdate(): void {
     for (const [itemTypeName, renderer] of this.diffRenderer.entries()) {
+      // "线"创建
       for (const [lineId, lineDiffItem] of this.lineDiffs.create.entries()) {
         const start = this.entities.get(lineDiffItem.startId)
         const end = this.entities.get(lineDiffItem.endId)
+
+        // 添加存在性检查
+        if (!start || !end) {
+          console.warn(`无法创建线 ${lineId}, 起点或终点不存在`)
+          continue
+        }
+
         if (start.t !== itemTypeName) {
           // 只通知起点对应的渲染器
           continue
@@ -137,9 +190,17 @@ export default class EntityManager {
         renderer.createLine(start, end, lineDiffItem.type)
       }
 
+      // "线"更新
       for (const [lineId, lineDiffItem] of this.lineDiffs.update.entries()) {
         const start = this.entities.get(lineDiffItem.startId)
         const end = this.entities.get(lineDiffItem.endId)
+
+        // 添加存在性检查
+        if (!start || !end) {
+          console.warn(`无法更新线 ${lineId}, 起点或终点不存在`)
+          continue
+        }
+
         if (start.t !== itemTypeName) {
           // 只通知起点对应的渲染器
           continue
@@ -147,13 +208,26 @@ export default class EntityManager {
         renderer.updateLine(start, end, lineDiffItem.type)
       }
 
+      // "线"删除
       for (const [lineId, lineDiffItem] of this.lineDiffs.delete.entries()) {
         const start = this.entities.get(lineDiffItem.startId)
         const end = this.entities.get(lineDiffItem.endId)
+
+        if (!start || !end) {
+          // 即使实体不存在也要处理删除
+          renderer.deleteLine(
+            start || { id: lineDiffItem.startId, t: 'unknown' } as ItemJson,
+            end || { id: lineDiffItem.endId, t: 'unknown' } as ItemJson,
+            lineDiffItem.type)
+          continue
+        }
+
         if (start.t !== itemTypeName) {
           // 只通知起点对应的渲染器
           continue
         }
+
+        // 使用安全删除方法, 即使实体不存在也要处理删除
         renderer.deleteLine(start, end, lineDiffItem.type)
       }
 
@@ -197,6 +271,11 @@ export default class EntityManager {
   }
 
   private updateReverseRelations(id: string, oldIds: Set<string>, newIds: Set<string>, relationType: LinkType) {
+    // 确保关系索引存在
+    if (!this.relationIndex.has(id)) {
+      this.relationIndex.set(id, new Relation())
+    }
+
     // 移除旧关系
     for (const relatedId of oldIds) {
       if (!newIds.has(relatedId)) {
@@ -219,6 +298,9 @@ export default class EntityManager {
   }
 
   private calculateLineDiffs(id: string, oldIds: Set<string>, newIds: Set<string>, lineType: LinkType) {
+    // 确保关系索引存在
+    if (!this.relationIndex.has(id)) return
+
     // 删除被移除的线
     for (const relatedId of oldIds) {
       if (!newIds.has(relatedId)) {
@@ -236,6 +318,43 @@ export default class EntityManager {
     }
   }
 
+
+  /**
+   * 删除关系关系网, 计算出差值, 可以临时放在 diffRenderer 中, 等待 commitUpdate 时统一处理
+   */
+  private removeRelations(id: string): void {
+    const relations = this.relationIndex.get(id)
+    if (!relations) return
+
+    relations.center.forEach(relatedId => {
+      const rev = this.relationIndex.get(relatedId)
+      if (rev) rev.center.delete(id)
+    })
+
+    relations.input.forEach(relatedId => {
+      const rev = this.relationIndex.get(relatedId)
+      if (rev) rev.output.delete(id)
+    })
+
+    relations.output.forEach(relatedId => {
+      const rev = this.relationIndex.get(relatedId)
+      if (rev) rev.input.delete(id)
+    })
+
+    this.relationIndex.delete(id)
+  }
+
+  private getDiffRenderer(type: string) {
+    let renderer = this.diffRenderer.get(type)
+    if (typeof renderer === 'undefined') {
+      renderer = getRenderer(type)
+      renderer.beginRendererUpdate(this.viewport)
+      this.diffRenderer.set(type, renderer)
+    }
+    return renderer
+  }
+
+
   /**
    * 重命名一个点
    * 注意, 不能在更新时刻改名. 所有的关系节点都应该改名
@@ -301,46 +420,6 @@ export default class EntityManager {
     }
   }
 
-  /**
-   * 删除关系关系网, 计算出差值, 可以临时放在 diffRenderer 中, 等待 commitUpdate 时统一处理
-   */
-  private removeRelations(id: string): void {
-    const relations = this.relationIndex.get(id)
-    if (!relations) return
-
-    const removeLine = (relatedId: string, type: LinkType) => {
-      const lineId = getLineId(id, relatedId, type)
-      this.lineDiffs.delete.set(lineId, { startId: id, endId: relatedId, type })
-    }
-
-    relations.center.forEach((relatedId) => {
-      this.relationIndex.get(relatedId)?.center.delete(id)
-      removeLine(relatedId, 'center')
-    })
-
-    relations.input.forEach((relatedId) => {
-      this.relationIndex.get(relatedId)?.output.delete(id)
-      removeLine(relatedId, 'in')
-    })
-
-    relations.output.forEach((relatedId) => {
-      this.relationIndex.get(relatedId)?.input.delete(id)
-      removeLine(relatedId, 'out')
-    })
-
-    this.relationIndex.delete(id)
-  }
-
-  private getDiffRenderer(type: string) {
-    let renderer = this.diffRenderer.get(type)
-    if (typeof renderer === 'undefined') {
-      renderer = getRenderer(type)
-      renderer.beginRendererUpdate(this.viewport)
-      this.diffRenderer.set(type, renderer)
-    }
-    return renderer
-  }
-
   deleteEntityOnly(id: string) {
     return this.entities.delete(id)
   }
@@ -376,30 +455,3 @@ interface LineDiffItem {
   type: LinkType
 }
 
-export class Relation {
-  center = new Set<string>()
-  input = new Set<string>()
-  output = new Set<string>()
-
-  add(type: LinkType, id: string) {
-    if (type === 'in')
-      return this.input.add(id)
-    else if (type === 'out')
-      return this.output.add(id)
-    else if (type === 'center')
-      return this.center.add(id)
-    else
-      throw new Error(`Unknown link type: ${type}`)
-  }
-
-  delete(type: LinkType, id: string) {
-    if (type === 'in')
-      return this.input.delete(id)
-    else if (type === 'out')
-      return this.output.delete(id)
-    else if (type === 'center')
-      return this.center.delete(id)
-    else
-      throw new Error(`Unknown link type: ${type}`)
-  }
-}
\ No newline at end of file
diff --git a/src/core/manager/StateManager.ts b/src/core/manager/StateManager.ts
index a2e7193..43b3c6c 100644
--- a/src/core/manager/StateManager.ts
+++ b/src/core/manager/StateManager.ts
@@ -40,11 +40,7 @@ interface HistoryStep {
  * stateManager.redo()
  *
  * // 用例2 添加
- * stateManager.beginStateUpdate();
- * stateManager.vdata.items[3].dt.center.push('p5');
- * stateManager.vdata.items.push({ id: 'p5', t: 'measure', tf: [[-6.0, 0, 8], [0, 0, 0], [0.25, 0.1, 0.25]], dt: { center: ['p4'] } });
- * stateManager.endStateUpdate();
- *
+ * stateManager.beginStateUpdate();stateManager.vdata.items[3].dt.center.push('p5');stateManager.vdata.items.push({ id: 'p5', t: 'measure', tf: [[-6.0, 0, 8], [0, 0, 0], [0.25, 0.1, 0.25]], dt: { center: ['p4'] } });stateManager.endStateUpdate();
  * stateManager.undo();
  * stateManager.redo();
  *
@@ -233,11 +229,6 @@ export default class StateManager {
 
     this.entityManager.beginEntityUpdate()
 
-    // 处理删除
-    for (const item of diff.removed) {
-      this.entityManager.deleteEntity(item.id)
-    }
-
     for (const item of diff.added) {
       this.entityManager.createOrUpdateEntity(item)
     }
@@ -246,6 +237,11 @@ export default class StateManager {
       this.entityManager.createOrUpdateEntity(after)
     }
 
+    // 最后处理删除
+    for (const item of diff.removed) {
+      this.entityManager.deleteEntity(item.id)
+    }
+
     this.entityManager.endEntityUpdate()
   }