diff --git a/app/(admin)/settings/admin-settings-client.tsx b/app/(admin)/settings/admin-settings-client.tsx
index 2147b71..290aafa 100644
--- a/app/(admin)/settings/admin-settings-client.tsx
+++ b/app/(admin)/settings/admin-settings-client.tsx
@@ -166,6 +166,8 @@ type SiteSettings = {
   tutorialVideoUrl: string | null;
   tutorialEnabled: boolean;
   rankingEnabled: boolean;
+  canvasEnabled: boolean;
+  canvasDefaultModelId: string | null;
 };
 
 type NavLink = {
@@ -378,6 +380,8 @@ export function AdminSettingsClient() {
     tutorialVideoUrl: null,
     tutorialEnabled: false,
     rankingEnabled: true,
+    canvasEnabled: true,
+    canvasDefaultModelId: null,
   });
 
   useEffect(() => {
@@ -403,6 +407,8 @@ export function AdminSettingsClient() {
         tutorialVideoUrl: siteSettingsData.tutorialVideoUrl || null,
         tutorialEnabled: siteSettingsData.tutorialEnabled ?? false,
         rankingEnabled: siteSettingsData.rankingEnabled ?? true,
+        canvasEnabled: siteSettingsData.canvasEnabled ?? true,
+        canvasDefaultModelId: siteSettingsData.canvasDefaultModelId || null,
       });
     }
   }, [siteSettingsData]);
@@ -2567,6 +2573,50 @@ export function AdminSettingsClient() {
                     </>
                   )}
                 </div>
+
+                {/* 无限画布设置 */}
+                <div className="border-t pt-4">
+                  <div className="flex items-center justify-between mb-4">
+                    <div className="space-y-0.5">
+                      <Label htmlFor="canvasEnabled">无限画布功能</Label>
+                      <div className="text-sm text-muted-foreground">
+                        开启后，用户可以使用无限画布进行图片编辑和生成
+                      </div>
+                    </div>
+                    <Switch
+                      id="canvasEnabled"
+                      checked={siteSettings.canvasEnabled}
+                      onCheckedChange={(checked) => setSiteSettings({ ...siteSettings, canvasEnabled: checked })}
+                    />
+                  </div>
+                  {siteSettings.canvasEnabled && (
+                    <div className="space-y-2">
+                      <Label htmlFor="canvasDefaultModelId">画布默认生图模型</Label>
+                      <Select
+                        value={siteSettings.canvasDefaultModelId || "auto"}
+                        onValueChange={(value) => setSiteSettings({ 
+                          ...siteSettings, 
+                          canvasDefaultModelId: value === "auto" ? null : value 
+                        })}
+                      >
+                        <SelectTrigger id="canvasDefaultModelId">
+                          <SelectValue placeholder="选择默认模型" />
+                        </SelectTrigger>
+                        <SelectContent>
+                          <SelectItem value="auto">智能自动（推荐）</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">
+                        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>
+                  )}
+                </div>
               </div>
               <Button onClick={handleSaveSiteSettings}>
                 <Save className="mr-2 h-4 w-4" /> 保存设置
diff --git a/app/api/site-settings/route.ts b/app/api/site-settings/route.ts
index a9faae4..552345a 100644
--- a/app/api/site-settings/route.ts
+++ b/app/api/site-settings/route.ts
@@ -41,6 +41,8 @@ export async function GET() {
         tutorialVideoUrl: null,
         tutorialEnabled: false,
         rankingEnabled: true,
+        canvasEnabled: true,
+        canvasDefaultModelId: null,
     };
     
     const response = NextResponse.json({
@@ -84,6 +86,8 @@ const updateSchema = z.object({
   tutorialVideoUrl: z.string().nullable().optional(),
   tutorialEnabled: z.boolean().optional(),
   rankingEnabled: z.boolean().optional(),
+  canvasEnabled: z.boolean().optional(),
+  canvasDefaultModelId: z.string().nullable().optional(),
 });
 
 // PUT /api/site-settings - 更新网站设置（仅管理员）
@@ -143,6 +147,8 @@ export async function PUT(request: NextRequest) {
           tutorialVideoUrl: data.tutorialVideoUrl,
           tutorialEnabled: data.tutorialEnabled ?? false,
           rankingEnabled: data.rankingEnabled ?? true,
+          canvasEnabled: data.canvasEnabled ?? true,
+          canvasDefaultModelId: data.canvasDefaultModelId,
           updatedBy: session.user.id,
         })
         .returning();
diff --git a/components/canvas/CanvasChatPanel.tsx b/components/canvas/CanvasChatPanel.tsx
index 0c76bee..c8db059 100644
--- a/components/canvas/CanvasChatPanel.tsx
+++ b/components/canvas/CanvasChatPanel.tsx
@@ -199,11 +199,13 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
     }>;
   }>("/api/models", fetcher);
 
-  // 获取网站设置（包含广告横幅配置）
+  // 获取网站设置（包含广告横幅配置和画布设置）
   const { data: siteSettings } = useSWR<{
     bannerEnabled?: boolean;
     bannerText?: string;
     bannerLink?: string | null;
+    canvasEnabled?: boolean;
+    canvasDefaultModelId?: string | null;
   }>("/api/site-settings", fetcher);
   
   // 过滤支持图片生成的模型
@@ -221,12 +223,14 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
   // 所有可选模型（智能自动 + 生图模型）
   const allModels = [SMART_AUTO_MODEL, ...imageModels];
   
-  // 默认选择智能自动模型
+  // 默认选择模型（根据系统设置）
   useEffect(() => {
-    if (!selectedModelId) {
-      setSelectedModelId("auto"); // 默认使用智能自动模式
+    if (!selectedModelId && siteSettings) {
+      // 使用系统设置的默认模型，如果没有设置则使用智能自动
+      const defaultModel = siteSettings.canvasDefaultModelId || "auto";
+      setSelectedModelId(defaultModel);
     }
-  }, [selectedModelId]);
+  }, [selectedModelId, siteSettings]);
   
   const currentModelIdRef = useRef(selectedModelId);
   const imageParamsRef = useRef(imageParams);
diff --git a/lib/db/schema.ts b/lib/db/schema.ts
index 28a2c56..7dceb68 100644
--- a/lib/db/schema.ts
+++ b/lib/db/schema.ts
@@ -306,6 +306,9 @@ export const siteSettings = pgTable("SiteSettings", {
   tutorialEnabled: boolean("tutorialEnabled").notNull().default(false), // 是否显示功能教程按钮
   // 精选榜设置
   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）
   updatedAt: timestamp("updatedAt").notNull().defaultNow(),
   updatedBy: uuid("updatedBy").references(() => user.id),
 });