diff --git a/apps/web/src/pages/generate/components/Step4TitleSettings.tsx b/apps/web/src/pages/generate/components/Step4TitleSettings.tsx
index 1ceb6fc95..aac2df0f2 100644
--- a/apps/web/src/pages/generate/components/Step4TitleSettings.tsx
+++ b/apps/web/src/pages/generate/components/Step4TitleSettings.tsx
@@ -21,34 +21,71 @@ const Step4TitleSettings: React.FC<Step4TitleSettingsProps> = (props) => {
     <div className="xx-form-section">
       <h3>📝 选择标题</h3>
 
-      <AiTitleGenerator
-        inputValue={t.aiTitleInput}
-        onInputChange={t.setAiTitleInput}
-        generating={t.aiTitleGenerating}
-        onGenerate={t.handleGenerateAiTitles}
-        results={t.aiTitleResults}
-        hasGenerated={t.hasGeneratedTitles}
-        onSelect={t.handleSelectAiTitle}
-        selectedTitle={t.titleSettings.title}
-        onRefresh={t.handleRefreshAiTitles}
-      />
+      {/* AI 自动选择模式 */}
+      {t.titleSettings.aiAutoSelect && (
+        <>
+          <div className="xx-title-ai-toggle">
+            <span className="xx-toggle-label">AI 自动选择标题</span>
+            <div className="xx-switch active" onClick={t.toggleAiAutoSelect}>
+              <div className="xx-switch-knob" />
+            </div>
+          </div>
 
-      <div className="xx-divider">
-        <span>或手动选择</span>
-      </div>
-
-      <div className="xx-title-ai-toggle">
-        <span className="xx-toggle-label">AI 自动选择标题</span>
-        <div
-          className={`xx-switch ${t.titleSettings.aiAutoSelect ? "active" : ""}`}
-          onClick={t.toggleAiAutoSelect}
-        >
-          <div className="xx-switch-knob" />
-        </div>
-      </div>
+          {/* 显示当前 AI 选中的标题（只读）+ 换一个按钮 */}
+          <div className="xx-form-field">
+            <label>当前 AI 选定标题</label>
+            <div
+              style={{
+                display: "flex",
+                alignItems: "center",
+                gap: 10,
+                padding: "8px 12px",
+                background: "var(--bg-secondary, rgba(0,0,0,0.04))",
+                borderRadius: 8,
+                fontSize: 14,
+                color: "var(--text-primary, #333)",
+              }}
+            >
+              <span style={{ flex: 1 }}>{t.titleSettings.title || "AI 将自动为你选择标题"}</span>
+              <button
+                type="button"
+                className="xx-btn xx-btn-primary"
+                style={{ flexShrink: 0, fontSize: 13, padding: "4px 12px" }}
+                onClick={t.autoGenerateTitle}
+              >
+                🔄 换一个
+              </button>
+            </div>
+          </div>
+        </>
+      )}
 
+      {/* 手动选择模式 */}
       {!t.titleSettings.aiAutoSelect && (
         <>
+          <AiTitleGenerator
+            inputValue={t.aiTitleInput}
+            onInputChange={t.setAiTitleInput}
+            generating={t.aiTitleGenerating}
+            onGenerate={t.handleGenerateAiTitles}
+            results={t.aiTitleResults}
+            hasGenerated={t.hasGeneratedTitles}
+            onSelect={t.handleSelectAiTitle}
+            selectedTitle={t.titleSettings.title}
+            onRefresh={t.handleRefreshAiTitles}
+          />
+
+          <div className="xx-divider">
+            <span>或手动选择</span>
+          </div>
+
+          <div className="xx-title-ai-toggle">
+            <span className="xx-toggle-label">AI 自动选择标题</span>
+            <div className="xx-switch" onClick={t.toggleAiAutoSelect}>
+              <div className="xx-switch-knob" />
+            </div>
+          </div>
+
           <div className="xx-form-field">
             <label>从标题库选择</label>
             <Select
@@ -83,24 +120,25 @@ const Step4TitleSettings: React.FC<Step4TitleSettingsProps> = (props) => {
               maxLength={50}
             />
           </div>
-
-          <TitleStylePanel
-            settings={t.titleSettings}
-            onUpdatePosition={t.updatePosition}
-            onUpdateFont={t.updateFont}
-            onUpdateSize={t.updateSize}
-            onToggleBold={t.toggleBold}
-            onToggleItalic={t.toggleItalic}
-            onToggleStroke={t.toggleStroke}
-            onToggleShadow={t.toggleShadow}
-            onApplyPreset={t.applyPreset}
-            activePreset={t.activePreset}
-            titlePresets={t.titlePresets}
-            POSITION_OPTIONS={POSITION_OPTIONS}
-            FONT_OPTIONS={FONT_OPTIONS}
-          />
         </>
       )}
+
+      {/* 样式面板始终可见，两种模式下都可调整标题展示样式 */}
+      <TitleStylePanel
+        settings={t.titleSettings}
+        onUpdatePosition={t.updatePosition}
+        onUpdateFont={t.updateFont}
+        onUpdateSize={t.updateSize}
+        onToggleBold={t.toggleBold}
+        onToggleItalic={t.toggleItalic}
+        onToggleStroke={t.toggleStroke}
+        onToggleShadow={t.toggleShadow}
+        onApplyPreset={t.applyPreset}
+        activePreset={t.activePreset}
+        titlePresets={t.titlePresets}
+        POSITION_OPTIONS={POSITION_OPTIONS}
+        FONT_OPTIONS={FONT_OPTIONS}
+      />
     </div>
   )
 }
diff --git a/apps/web/src/pages/generate/hooks/generate-video/buildPayload.ts b/apps/web/src/pages/generate/hooks/generate-video/buildPayload.ts
index 6040cf875..ced8ec345 100644
--- a/apps/web/src/pages/generate/hooks/generate-video/buildPayload.ts
+++ b/apps/web/src/pages/generate/hooks/generate-video/buildPayload.ts
@@ -63,7 +63,8 @@ export const buildEditPlanPayload = (props: UseGenerateVideoProps) => {
 export const validateGenerateInputs = (props: UseGenerateVideoProps): string | null => {
   const { titleSettings, materialMode, selectedMaterials, voiceMode, selectedClonedVoice } = props
 
-  if (!titleSettings.title.trim()) {
+  // AI 自动选择模式下，标题可以为空（后端会自行生成）
+  if (!titleSettings.aiAutoSelect && !titleSettings.title?.trim()) {
     return "请先选择或输入标题"
   }
   if (materialMode === "manual" && selectedMaterials.length === 0) {
diff --git a/apps/web/src/pages/generate/hooks/useStep4Title/index.ts b/apps/web/src/pages/generate/hooks/useStep4Title/index.ts
index eb8114623..3f6aaac81 100644
--- a/apps/web/src/pages/generate/hooks/useStep4Title/index.ts
+++ b/apps/web/src/pages/generate/hooks/useStep4Title/index.ts
@@ -1,3 +1,4 @@
+import { useEffect, useRef } from "react"
 import { useQuery } from "@tanstack/react-query"
 import { getTitles } from "@/api/titles"
 import type { TitleSettings } from "../../types"
@@ -22,27 +23,59 @@ export function useStep4Title({ titleSettings, onTitleSettingsChange }: UseStep4
   })
 
   // AI 标题生成
-  const aiGenerator = useAiTitleGenerator({ titleSettings, onTitleSettingsChange })
+  const {
+    aiTitleInput,
+    setAiTitleInput,
+    aiTitleGenerating,
+    aiTitleResults,
+    hasGeneratedTitles,
+    handleGenerateAiTitles,
+    handleSelectAiTitle,
+    handleRefreshAiTitles,
+    autoGenerateTitle,
+  } = useAiTitleGenerator({ titleSettings, onTitleSettingsChange })
 
   // 样式更新
   const styleUpdaters = useTitleStyleUpdaters({ titleSettings, onTitleSettingsChange })
 
+  // 追踪 AI 自动选择开关的上一次值 & 是否首次挂载
+  const prevAiAutoSelect = useRef(titleSettings.aiAutoSelect)
+  const isFirstMount = useRef(true)
+
+  // 当 AI 自动选择开关打开时，自动生成/选择一个标题填入
+  // 首次挂载时如果开关已经是 true 且无标题，也需要触发
+  useEffect(() => {
+    if (isFirstMount.current) {
+      isFirstMount.current = false
+      if (titleSettings.aiAutoSelect && !titleSettings.title) {
+        autoGenerateTitle()
+      }
+      prevAiAutoSelect.current = titleSettings.aiAutoSelect
+      return
+    }
+    if (titleSettings.aiAutoSelect && !prevAiAutoSelect.current && !titleSettings.title) {
+      autoGenerateTitle()
+    }
+    prevAiAutoSelect.current = titleSettings.aiAutoSelect
+  }, [titleSettings.aiAutoSelect, titleSettings.title, autoGenerateTitle])
+
   return {
     // 数据
     userTitles,
     titleSettings,
     // AI 标题状态
-    aiTitleInput: aiGenerator.aiTitleInput,
-    setAiTitleInput: aiGenerator.setAiTitleInput,
-    aiTitleGenerating: aiGenerator.aiTitleGenerating,
-    aiTitleResults: aiGenerator.aiTitleResults,
-    hasGeneratedTitles: aiGenerator.hasGeneratedTitles,
+    aiTitleInput,
+    setAiTitleInput,
+    aiTitleGenerating,
+    aiTitleResults,
+    hasGeneratedTitles,
     activePreset: styleUpdaters.activePreset,
     titlePresets: styleUpdaters.titlePresets,
     // AI 标题操作
-    handleGenerateAiTitles: aiGenerator.handleGenerateAiTitles,
-    handleSelectAiTitle: aiGenerator.handleSelectAiTitle,
-    handleRefreshAiTitles: aiGenerator.handleRefreshAiTitles,
+    handleGenerateAiTitles,
+    handleSelectAiTitle,
+    handleRefreshAiTitles,
+    autoGenerateTitle,
     // 标题设置操作
     updateTitle: styleUpdaters.updateTitle,
     toggleAiAutoSelect: styleUpdaters.toggleAiAutoSelect,
diff --git a/apps/web/src/pages/generate/hooks/useStep4Title/useAiTitleGenerator.ts b/apps/web/src/pages/generate/hooks/useStep4Title/useAiTitleGenerator.ts
index 0e2f778bd..b765259a6 100644
--- a/apps/web/src/pages/generate/hooks/useStep4Title/useAiTitleGenerator.ts
+++ b/apps/web/src/pages/generate/hooks/useStep4Title/useAiTitleGenerator.ts
@@ -72,9 +72,30 @@ export function useAiTitleGenerator({
     setAiTitleGenerating(false)
   }, [aiTitleInput])
 
+  /**
+   * 自动生成标题（供 AI 自动选择开关使用）
+   * 如果已有生成结果，直接从中选一个；否则用默认关键词生成
+   */
+  const autoGenerateTitle = useCallback((): string => {
+    if (aiTitleResults.length > 0) {
+      const picked = aiTitleResults[Math.floor(Math.random() * aiTitleResults.length)]
+      if (!picked) return ""
+      onTitleSettingsChange({ ...titleSettings, title: picked.title })
+      return picked.title
+    }
+    // 没有已有结果，用默认关键词生成
+    const results = generateTitlesFromTopic("短视频")
+    setAiTitleResults(results)
+    setHasGeneratedTitles(true)
+    const picked = results[Math.floor(Math.random() * results.length)]
+    if (!picked) return ""
+    onTitleSettingsChange({ ...titleSettings, title: picked.title })
+    return picked.title
+  }, [aiTitleResults, titleSettings, onTitleSettingsChange])
+
   const handleSelectAiTitle = useCallback(
     (title: string) => {
-      onTitleSettingsChange({ ...titleSettings, title, aiAutoSelect: false })
+      onTitleSettingsChange({ ...titleSettings, title })
       message.success("已选用此标题")
     },
     [titleSettings, onTitleSettingsChange],
@@ -98,5 +119,6 @@ export function useAiTitleGenerator({
     handleGenerateAiTitles,
     handleSelectAiTitle,
     handleRefreshAiTitles,
+    autoGenerateTitle,
   }
 }