diff --git a/app/(admin)/settings/admin-settings-client.tsx b/app/(admin)/settings/admin-settings-client.tsx
index 290aafa2f..7094f4d0e 100644
--- a/app/(admin)/settings/admin-settings-client.tsx
+++ b/app/(admin)/settings/admin-settings-client.tsx
@@ -168,6 +168,7 @@ type SiteSettings = {
   rankingEnabled: boolean;
   canvasEnabled: boolean;
   canvasDefaultModelId: string | null;
+  canvasAutoModeDefaultModelId: string | null;
 };
 
 type NavLink = {
@@ -382,6 +383,7 @@ export function AdminSettingsClient() {
     rankingEnabled: true,
     canvasEnabled: true,
     canvasDefaultModelId: null,
+    canvasAutoModeDefaultModelId: null,
   });
 
   useEffect(() => {
@@ -409,6 +411,7 @@ export function AdminSettingsClient() {
         rankingEnabled: siteSettingsData.rankingEnabled ?? true,
         canvasEnabled: siteSettingsData.canvasEnabled ?? true,
         canvasDefaultModelId: siteSettingsData.canvasDefaultModelId || null,
+        canvasAutoModeDefaultModelId: siteSettingsData.canvasAutoModeDefaultModelId || null,
       });
     }
   }, [siteSettingsData]);
@@ -2615,6 +2618,33 @@ export function AdminSettingsClient() {
                         设置无限画布中用户的默认生图模型。"智能自动"会根据用户需求自动选择最佳模型。
                       </div>
                     </div>
+                    
+                    {/* 智能自动模式下的默认生图模型 */}
+                    <div className="space-y-2 mt-4 pt-4 border-t">
+                      <Label htmlFor="canvasAutoModeDefaultModelId">智能自动模式 - 默认生图模型</Label>
+                      <Select
+                        value={siteSettings.canvasAutoModeDefaultModelId || "system"}
+                        onValueChange={(value) => setSiteSettings({ 
+                          ...siteSettings, 
+                          canvasAutoModeDefaultModelId: value === "system" ? null : value 
+                        })}
+                      >
+                        <SelectTrigger id="canvasAutoModeDefaultModelId">
+                          <SelectValue placeholder="选择默认模型" />
+                        </SelectTrigger>
+                        <SelectContent>
+                          <SelectItem value="system">系统智能选择（根据意图路由）</SelectItem>
+                          {modelsData?.models?.filter((m: any) => m.supportsImageGen).map((model: any) => (
+                            <SelectItem key={model.id} value={model.id}>
+                              {model.displayName}
+                            </SelectItem>
+                          ))}
+                        </SelectContent>
+                      </Select>
+                      <div className="text-xs text-muted-foreground">
+                        当用户选择"智能自动"模式时，系统实际使用的生图模型。"系统智能选择"会根据用户意图（如抠图、换背景等）自动路由到最佳模型。
+                      </div>
+                    </div>
                   )}
                 </div>
               </div>
diff --git a/app/api/site-settings/route.ts b/app/api/site-settings/route.ts
index 552345ac3..8f8252298 100644
--- a/app/api/site-settings/route.ts
+++ b/app/api/site-settings/route.ts
@@ -43,6 +43,7 @@ export async function GET() {
         rankingEnabled: true,
         canvasEnabled: true,
         canvasDefaultModelId: null,
+        canvasAutoModeDefaultModelId: null,
     };
     
     const response = NextResponse.json({
@@ -88,6 +89,7 @@ const updateSchema = z.object({
   rankingEnabled: z.boolean().optional(),
   canvasEnabled: z.boolean().optional(),
   canvasDefaultModelId: z.string().nullable().optional(),
+  canvasAutoModeDefaultModelId: z.string().nullable().optional(),
 });
 
 // PUT /api/site-settings - 更新网站设置（仅管理员）
@@ -149,6 +151,7 @@ export async function PUT(request: NextRequest) {
           rankingEnabled: data.rankingEnabled ?? true,
           canvasEnabled: data.canvasEnabled ?? true,
           canvasDefaultModelId: data.canvasDefaultModelId,
+          canvasAutoModeDefaultModelId: data.canvasAutoModeDefaultModelId,
           updatedBy: session.user.id,
         })
         .returning();
diff --git a/lib/ai/model-router.ts b/lib/ai/model-router.ts
index 9261ff557..b40e2b384 100644
--- a/lib/ai/model-router.ts
+++ b/lib/ai/model-router.ts
@@ -110,10 +110,36 @@ export async function routeToModel(params: {
 
   // 使用动态导入避免循环依赖
   const { getEnabledAiModelsWithProvider } = await import("@/lib/db/queries");
+  const { db } = await import("@/lib/db");
+  const { siteSettings } = await import("@/lib/db/schema");
   
   // 获取所有可用模型
   const allModels = await getEnabledAiModelsWithProvider();
   console.log("[Model Router] Available models:", allModels.length);
+  
+  // 🆕 检查是否有配置的默认生图模型
+  const [settings] = await db.select().from(siteSettings).limit(1);
+  const configuredDefaultModelId = settings?.canvasAutoModeDefaultModelId;
+  
+  if (configuredDefaultModelId) {
+    // 如果配置了默认模型，直接使用该模型
+    const configuredModel = allModels.find(
+      (m) => m.model.id === configuredDefaultModelId && m.model.isEnabled && !m.model.isSubModel
+    );
+    
+    if (configuredModel) {
+      console.log("[Model Router] ✅ Using configured default model:", configuredModel.model.displayName);
+      return {
+        id: configuredModel.model.id,
+        displayName: configuredModel.model.displayName,
+        providerType: configuredModel.provider.type,
+        modelId: configuredModel.model.modelId,
+        reason: `管理员配置的默认模型 → ${configuredModel.model.displayName}`,
+      };
+    } else {
+      console.log("[Model Router] ⚠️ Configured default model not found or disabled, falling back to intent routing");
+    }
+  }
 
   // 获取意图对应的配置
   let config = INTENT_MODEL_MAP[intent] || INTENT_MODEL_MAP["chat"];
diff --git a/lib/db/schema.ts b/lib/db/schema.ts
index 7dceb6890..9d69c7dfd 100644
--- a/lib/db/schema.ts
+++ b/lib/db/schema.ts
@@ -308,7 +308,8 @@ export const siteSettings = pgTable("SiteSettings", {
   rankingEnabled: boolean("rankingEnabled").notNull().default(true), // 是否显示精选榜按钮
   // 无限画布设置
   canvasEnabled: boolean("canvasEnabled").notNull().default(true), // 是否启用无限画布功能
-  canvasDefaultModelId: varchar("canvasDefaultModelId", { length: 128 }), // 画布默认生图模型ID（null表示智能自动）
+  canvasDefaultModelId: varchar("canvasDefaultModelId", { length: 128 }), // 画布默认选择的模型ID（null表示智能自动）
+  canvasAutoModeDefaultModelId: varchar("canvasAutoModeDefaultModelId", { length: 128 }), // 智能自动模式下实际使用的默认生图模型ID
   updatedAt: timestamp("updatedAt").notNull().defaultNow(),
   updatedBy: uuid("updatedBy").references(() => user.id),
 });