diff --git a/src/main/services/git/GitService.ts b/src/main/services/git/GitService.ts
index 3fc4755e..d2df0186 100644
--- a/src/main/services/git/GitService.ts
+++ b/src/main/services/git/GitService.ts
@@ -436,10 +436,11 @@ export class GitService {
   }
 
   async checkout(branch: string): Promise<void> {
-    // Remote branch names are in the format "remotes/origin/branch-name"
-    // git checkout requires "origin/branch-name" format to properly track remote branches
-    const normalizedBranch = branch.startsWith('remotes/') ? branch.slice(8) : branch;
-    await this.git.checkout(normalizedBranch);
+    if (branch.startsWith('remotes/')) {
+      await this.checkoutRemoteBranch(this.git, branch);
+    } else {
+      await this.git.checkout(branch);
+    }
   }
 
   async createBranch(name: string, startPoint?: string): Promise<void> {
@@ -1118,6 +1119,38 @@ export class GitService {
     }
   }
 
+  /**
+   * Checkout a remote branch by extracting the local branch name and creating
+   * a tracking branch if it does not exist locally.
+   * @param git - SimpleGit instance (main repo or submodule)
+   * @param branch - Remote branch name in format "remotes/origin/branch-name"
+   */
+  private async checkoutRemoteBranch(git: SimpleGit, branch: string): Promise<void> {
+    // "remotes/origin/dev" → remoteBranch="origin/dev", localBranch="dev"
+    const remoteBranch = branch.slice(8);
+    const slashIdx = remoteBranch.indexOf('/');
+    const localBranch = slashIdx >= 0 ? remoteBranch.slice(slashIdx + 1) : remoteBranch;
+
+    try {
+      // Prefer switching to existing local branch
+      await git.checkout(localBranch);
+    } catch (error) {
+      // Check if error is due to branch not existing
+      const msg = error instanceof Error ? error.message : String(error);
+      if (
+        msg.includes('did not match') ||
+        msg.includes('pathspec') ||
+        msg.includes('unknown revision')
+      ) {
+        // Local branch does not exist: create it and track the remote
+        await git.checkout(['-b', localBranch, '--track', remoteBranch]);
+      } else {
+        // Re-throw other errors (e.g., uncommitted changes blocking checkout)
+        throw error;
+      }
+    }
+  }
+
   /**
    * Fetch 单个子模块
    */
@@ -1333,11 +1366,17 @@ export class GitService {
   }
 
   /**
-   * 切换子模块分支
+   * Checkout a branch in a submodule.
+   * Handles remote tracking refs (remotes/origin/dev) by extracting the local
+   * branch name and creating a tracking branch when it does not exist locally.
    */
   async checkoutSubmoduleBranch(submodulePath: string, branch: string): Promise<void> {
     const subGit = this.getSubmoduleGit(submodulePath);
-    await subGit.checkout(branch);
+    if (branch.startsWith('remotes/')) {
+      await this.checkoutRemoteBranch(subGit, branch);
+    } else {
+      await subGit.checkout(branch);
+    }
   }
 
   // Static methods for clone operations
diff --git a/src/renderer/components/source-control/SourceControlPanel.tsx b/src/renderer/components/source-control/SourceControlPanel.tsx
index 8f624ebc..10ff8ddb 100644
--- a/src/renderer/components/source-control/SourceControlPanel.tsx
+++ b/src/renderer/components/source-control/SourceControlPanel.tsx
@@ -33,6 +33,7 @@ import {
   useGitUnstage,
 } from '@/hooks/useSourceControl';
 import {
+  useCheckoutSubmoduleBranch,
   useStageSubmodule,
   useSubmoduleBranches,
   useSubmoduleChanges,
@@ -128,6 +129,7 @@ export function SourceControlPanel({
     refetch: refetchBranches,
   } = useGitBranches(rootPath ?? null);
   const checkoutMutation = useGitCheckout();
+  const checkoutSubmoduleMutation = useCheckoutSubmoduleBranch();
 
   // Submodules
   const { data: submodules = [] } = useSubmodules(rootPath ?? null);
@@ -397,21 +399,42 @@ export function SourceControlPanel({
     [rootPath, repositories, pushMutation, queryClient, refetchStatus, refetch, refetchCommits, t]
   );
 
-  // Branch checkout handler
+  // Branch checkout handler - handles both main repo and submodule branches
   const handleBranchCheckout = useCallback(
     async (repoPath: string, branch: string) => {
-      if (!repoPath || checkoutMutation.isPending) return;
+      const isPending = checkoutMutation.isPending || checkoutSubmoduleMutation.isPending;
+      if (!repoPath || isPending) return;
+
+      // Detect submodule by matching repoPath against the submodule list
+      const submodule = submodules.find((s) => rootPath && repoPath === joinPath(rootPath, s.path));
 
       try {
-        await checkoutMutation.mutateAsync({ workdir: repoPath, branch });
-        refetch();
-        refetchBranches();
-        refetchCommits();
-        refetchStatus();
+        if (submodule && rootPath) {
+          // Use dedicated submodule mutation so onSuccess invalidates
+          // ['git', 'submodules', rootPath] — the correct cache key
+          await checkoutSubmoduleMutation.mutateAsync({
+            workdir: rootPath,
+            submodulePath: submodule.path,
+            branch,
+          });
+          refetchSubmoduleChanges();
+          refetchSubmoduleCommits();
+        } else {
+          await checkoutMutation.mutateAsync({ workdir: repoPath, branch });
+          refetch();
+          refetchBranches();
+          refetchCommits();
+          refetchStatus();
+        }
+
+        // Normalize branch name for display (remotes/origin/dev → dev)
+        const displayBranch = branch.startsWith('remotes/')
+          ? branch.slice(branch.indexOf('/', 8) + 1)
+          : branch;
 
         toastManager.add({
           title: t('Branch switched'),
-          description: t('Branch switched to {{branch}}', { branch }),
+          description: t('Branch switched to {{branch}}', { branch: displayBranch }),
           type: 'success',
           timeout: 3000,
         });
@@ -424,7 +447,19 @@ export function SourceControlPanel({
         });
       }
     },
-    [checkoutMutation, refetch, refetchBranches, refetchCommits, refetchStatus, t]
+    [
+      checkoutMutation,
+      checkoutSubmoduleMutation,
+      submodules,
+      rootPath,
+      refetch,
+      refetchBranches,
+      refetchCommits,
+      refetchStatus,
+      refetchSubmoduleChanges,
+      refetchSubmoduleCommits,
+      t,
+    ]
   );
 
   // Flatten infinite query data
@@ -810,7 +845,7 @@ export function SourceControlPanel({
                 onSync={handleSync}
                 onPublish={handlePublish}
                 onCheckout={handleBranchCheckout}
-                isCheckingOut={checkoutMutation.isPending}
+                isCheckingOut={checkoutMutation.isPending || checkoutSubmoduleMutation.isPending}
               />
 
               {/* Changes Section (Collapsible) */}
@@ -849,7 +884,9 @@ export function SourceControlPanel({
                       selectedRepoPath && handleBranchCheckout(selectedRepoPath, branch)
                     }
                     isLoading={currentBranchesLoading}
-                    isCheckingOut={checkoutMutation.isPending}
+                    isCheckingOut={
+                      checkoutMutation.isPending || checkoutSubmoduleMutation.isPending
+                    }
                     size="xs"
                   />
                 </div>