diff --git a/apps/web/src/pages/editing-planner/components/TimelinePanel.tsx b/apps/web/src/pages/editing-planner/components/TimelinePanel.tsx
index cc418e343..bc59991a4 100755
--- a/apps/web/src/pages/editing-planner/components/TimelinePanel.tsx
+++ b/apps/web/src/pages/editing-planner/components/TimelinePanel.tsx
@@ -3,7 +3,13 @@
  * 时间标尺(20px) + 水平片段卡片轨道(100x100) + HTML5拖拽排序
  * "+" 卡片 → 类型+时长选择器
  */
-import React, { useState, useRef, useCallback, useEffect } from "react";
+import React, {
+  useState,
+  useRef,
+  useCallback,
+  useEffect,
+  useLayoutEffect,
+} from "react";
 import type { ClipData, ClipType } from "../types";
 
 interface TimelinePanelProps {
@@ -60,32 +66,24 @@ const TimelinePanel: React.FC<TimelinePanelProps> = ({
         ? ["pip"]
         : ["voice", "pip"]; // voice_pip 或默认
 
-  /* ── 面板尺寸估算（用于边界检测） ── */
-  const PICKER_H = 200; // 面板预估高度（padding + 标题 + 类型行 + 时长行 + 按钮 + 间距）
+  /* ── 面板尺寸（宽度固定，高度由 useLayoutEffect 实测） ── */
   const PICKER_W = 240; // 面板宽度（与 CSS 一致）
   const GAP = 6; // 面板与"+"卡片的间距
 
-  /* ── 计算 picker 弹出位置（fixed 定位 + 视口边界检测） ── */
+  /* ── 计算 picker 初始位置（默认从"+"按钮上方弹出） ── */
   const updatePickerPosition = useCallback(() => {
     if (!addCardRef.current) return;
     const rect = addCardRef.current.getBoundingClientRect();
     const vw = window.innerWidth;
-    const vh = window.innerHeight;
 
-    /* 垂直方向：优先向下弹出；空间不足则向上翻转 */
-    let top: number;
-    if (rect.bottom + GAP + PICKER_H > vh) {
-      // 下方空间不够 → 向上弹出
-      top = rect.top - GAP - PICKER_H;
-      if (top < 8) top = 8; // 极端情况： clamp 到视口顶部
-    } else {
-      top = rect.bottom + GAP;
-    }
+    /* 垂直方向：默认向上弹出（上方空间永远比下方大） */
+    const roughHeight = 180; // 粗略估算，useLayoutEffect 会用实际高度校正
+    let top = rect.top - GAP - roughHeight;
+    if (top < 8) top = 8;
 
     /* 水平方向：右对齐"+"卡片；太靠右超出视口则左移 */
     let right = vw - rect.right;
     if (rect.right - PICKER_W < 8) {
-      // 左边界保护
       right = vw - PICKER_W - 8;
     }
 
@@ -99,36 +97,36 @@ const TimelinePanel: React.FC<TimelinePanelProps> = ({
     setShowAddPicker((v) => !v);
   };
 
-  /* ── 渲染后用实际面板高度做精确边界校正 ── */
-  useEffect(() => {
-    if (!showAddPicker || !pickerRef.current) return;
-    const pickerRect = pickerRef.current.getBoundingClientRect();
+  /* ── 渲染后用实际 offsetHeight 做精确边界校正（useLayoutEffect 确保 paint 前完成） ── */
+  useLayoutEffect(() => {
+    if (!showAddPicker || !pickerRef.current || !addCardRef.current) return;
+    const pickerEl = pickerRef.current;
+    const addRect = addCardRef.current.getBoundingClientRect();
+    const pickerH = pickerEl.offsetHeight; // 实际高度，不用硬编码
     const vh = window.innerHeight;
     const vw = window.innerWidth;
 
-    let adjustTop: number | null = null;
-    let adjustRight: number | null = null;
+    /* 默认：面板在"+"按钮上方 */
+    let top = addRect.top - GAP - pickerH;
 
-    // 底部溢出 → 上移
-    if (pickerRect.bottom > vh - 8) {
-      adjustTop = vh - 8 - pickerRect.height;
-      if (adjustTop < 8) adjustTop = 8;
+    /* 上方空间也不够（极端情况）→ 翻转到下方 */
+    if (top < 8) {
+      top = addRect.bottom + GAP;
+      /* 下方也溢出 → clamp */
+      if (top + pickerH > vh - 8) {
+        top = vh - 8 - pickerH;
+        if (top < 8) top = 8;
+      }
     }
-    // 顶部溢出 → 下移
-    if (pickerRect.top < 8) {
-      adjustTop = 8;
-    }
-    // 左侧溢出 → 左移（right 增大）
+
+    /* 水平方向：右对齐"+"卡片；左侧溢出保护 */
+    let right = vw - addRect.right;
+    const pickerRect = pickerEl.getBoundingClientRect();
     if (pickerRect.left < 8) {
-      adjustRight = vw - PICKER_W - 8;
+      right = vw - PICKER_W - 8;
     }
 
-    if (adjustTop !== null || adjustRight !== null) {
-      setPickerPos((prev) => ({
-        top: adjustTop ?? prev.top,
-        right: adjustRight ?? prev.right,
-      }));
-    }
+    setPickerPos({ top, right });
   }, [showAddPicker]);
 
   /* ── 点击外部关闭添加面板 ── */