diff --git a/src/review/context/diff-extractor.ts b/src/review/context/diff-extractor.ts
index 0a4683a..305c79a 100644
--- a/src/review/context/diff-extractor.ts
+++ b/src/review/context/diff-extractor.ts
@@ -38,7 +38,8 @@ export class DiffExtractor {
   async buildContext(
     run: ReviewRun,
     mirrorPath: string,
-    workspacePath: string
+    workspacePath: string,
+    lastReviewedHead?: string
   ): Promise<ReviewContext> {
     const targetSha = run.headSha || run.commitSha;
     if (!targetSha) {
@@ -46,6 +47,11 @@ export class DiffExtractor {
     }
 
     let baseSha = run.baseSha;
+    // 增量审查：如果提供了 lastReviewedHead，用它替换 baseSha
+    const incremental = !!lastReviewedHead;
+    if (lastReviewedHead) {
+      baseSha = lastReviewedHead;
+    }
     if (!baseSha) {
       baseSha =
         (await this.localRepoManager.resolveCommitParent(workspacePath, targetSha)) || undefined;
@@ -55,11 +61,11 @@ export class DiffExtractor {
     const isRootCommit = !baseSha;
     const diff = isRootCommit
       ? await this.getRootCommitDiff(workspacePath, targetSha)
-      : await this.getDiff(workspacePath, run.eventType, baseSha!, targetSha);
+      : await this.getDiff(workspacePath, run.eventType, baseSha!, targetSha, incremental);
 
     const changedFiles = isRootCommit
       ? await this.getRootCommitChangedFiles(workspacePath, targetSha)
-      : await this.getChangedFiles(workspacePath, baseSha!, targetSha);
+      : await this.getChangedFiles(workspacePath, baseSha!, targetSha, incremental);
 
     // 构建允许的文件路径集合，确保parsedDiff也受REVIEW_MAX_FILES_PER_RUN限制
     const allowedPaths = new Set(changedFiles.map((f) => f.path));
@@ -103,12 +109,13 @@ export class DiffExtractor {
     workspacePath: string,
     eventType: ReviewRun['eventType'],
     baseSha: string,
-    targetSha: string
+    targetSha: string,
+    incremental = false
   ): Promise<string> {
     if (eventType === 'pull_request') {
       const response = await this.sandboxExec.run(
         'git',
-        ['diff', '--unified=3', `${baseSha}...${targetSha}`],
+        ['diff', '--unified=3', `${baseSha}${incremental ? '..' : '...'}${targetSha}`],
         {
           cwd: workspacePath,
           timeoutMs: this.commandTimeoutMs,
@@ -197,11 +204,12 @@ export class DiffExtractor {
   private async getChangedFiles(
     workspacePath: string,
     baseSha: string,
-    targetSha: string
+    targetSha: string,
+    incremental = false
   ): Promise<ChangedFile[]> {
     const statusResult = await this.sandboxExec.run(
       'git',
-      ['diff', '--name-status', `${baseSha}...${targetSha}`],
+      ['diff', '--name-status', `${baseSha}${incremental ? '..' : '...'}${targetSha}`],
       {
         cwd: workspacePath,
         timeoutMs: this.commandTimeoutMs,
@@ -210,7 +218,7 @@ export class DiffExtractor {
 
     const numStatResult = await this.sandboxExec.run(
       'git',
-      ['diff', '--numstat', `${baseSha}...${targetSha}`],
+      ['diff', '--numstat', `${baseSha}${incremental ? '..' : '...'}${targetSha}`],
       {
         cwd: workspacePath,
         timeoutMs: this.commandTimeoutMs,
diff --git a/src/review/context/local-repo-manager.ts b/src/review/context/local-repo-manager.ts
index 912725d..912e405 100644
--- a/src/review/context/local-repo-manager.ts
+++ b/src/review/context/local-repo-manager.ts
@@ -112,7 +112,7 @@ export class LocalRepoManager {
         // fetch使用认证参数
         await this.sandboxExec.run(
           'git',
-          [...authArgs, '--git-dir', mirrorPath, 'fetch', '--prune', 'origin', '+refs/*:refs/*'],
+          [...authArgs, '--git-dir', mirrorPath, 'fetch', '--prune', 'origin', '+refs/*:refs/*', '^refs/reviewed/*'],
           {
             cwd: this.workDir,
             timeoutMs: this.commandTimeoutMs,
@@ -247,4 +247,69 @@ export class LocalRepoManager {
       return false;
     }
   }
+
+  /**
+   * 保存审查快照 ref，记录 PR 最后一次成功审查的 baseSha 和 headSha
+   * 存储在 mirror 的 refs/reviewed/pr/{prNumber}/head 和 refs/reviewed/pr/{prNumber}/base
+   */
+  async saveReviewedRef(mirrorPath: string, prNumber: number, baseSha: string, headSha: string): Promise<void> {
+    const unlock = await this.acquireMirrorLock(mirrorPath);
+    try {
+      const headRef = `refs/reviewed/pr/${prNumber}/head`;
+      const baseRef = `refs/reviewed/pr/${prNumber}/base`;
+      await this.sandboxExec.run(
+        'git',
+        ['--git-dir', mirrorPath, 'update-ref', headRef, headSha],
+        {
+          cwd: this.workDir,
+          timeoutMs: this.commandTimeoutMs,
+        }
+      );
+      await this.sandboxExec.run(
+        'git',
+        ['--git-dir', mirrorPath, 'update-ref', baseRef, baseSha],
+        {
+          cwd: this.workDir,
+          timeoutMs: this.commandTimeoutMs,
+        }
+      );
+      logger.info('已保存审查快照 ref', { mirrorPath, prNumber, baseSha, headSha });
+    } finally {
+      unlock();
+    }
+  }
+
+  /**
+   * 解析上次审查的快照（baseSha + headSha）
+   * 如果任一 ref 不存在，返回 null
+   */
+  async resolveReviewedRef(mirrorPath: string, prNumber: number): Promise<{ baseSha: string; headSha: string } | null> {
+    try {
+      const headRef = `refs/reviewed/pr/${prNumber}/head`;
+      const baseRef = `refs/reviewed/pr/${prNumber}/base`;
+      const headResult = await this.sandboxExec.run(
+        'git',
+        ['--git-dir', mirrorPath, 'rev-parse', '--verify', headRef],
+        {
+          cwd: this.workDir,
+          timeoutMs: this.commandTimeoutMs,
+        }
+      );
+      const baseResult = await this.sandboxExec.run(
+        'git',
+        ['--git-dir', mirrorPath, 'rev-parse', '--verify', baseRef],
+        {
+          cwd: this.workDir,
+          timeoutMs: this.commandTimeoutMs,
+        }
+      );
+      const headSha = headResult.stdout.trim();
+      const baseSha = baseResult.stdout.trim();
+      if (!headSha || !baseSha) return null;
+      return { baseSha, headSha };
+    } catch {
+      return null;
+    }
+  }
+
 }
diff --git a/src/review/orchestrator.ts b/src/review/orchestrator.ts
index c72525d..7298122 100644
--- a/src/review/orchestrator.ts
+++ b/src/review/orchestrator.ts
@@ -171,6 +171,34 @@ export class ReviewOrchestrator {
         latencyMs: Date.now() - workspaceStepStart,
       });
 
+      // ── 增量审查基线解析 ─────────────────────────────────────────────
+      let lastReviewedHead: string | undefined;
+      if (run.eventType === 'pull_request' && run.prNumber) {
+        const snapshot = await this.localRepoManager.resolveReviewedRef(
+          repoPaths.mirrorPath,
+          run.prNumber
+        );
+        if (snapshot && targetSha) {
+          if (snapshot.baseSha === run.baseSha) {
+            // base 未变（追加 commit 或 force-push 修改 commit）→ 增量审查
+            lastReviewedHead = snapshot.headSha;
+            logger.info('增量审查模式：使用上次审查快照', {
+              runId: run.id,
+              lastReviewedHead: snapshot.headSha,
+              currentHead: targetSha,
+              baseSha: run.baseSha,
+            });
+          } else {
+            // base 变了（PR 分支做了 rebase）→ 全量审查
+            logger.info('PR base 已变更（可能 rebase），回退全量审查', {
+              runId: run.id,
+              savedBaseSha: snapshot.baseSha,
+              currentBaseSha: run.baseSha,
+            });
+          }
+        }
+      }
+
       const contextStart = Date.now();
       await this.store.addStep({
         runId: run.id,
@@ -182,7 +210,8 @@ export class ReviewOrchestrator {
       const context = await this.diffExtractor.buildContext(
         run,
         repoPaths.mirrorPath,
-        repoPaths.workspacePath
+        repoPaths.workspacePath,
+        lastReviewedHead
       );
 
       await this.store.addStep({
@@ -477,6 +506,23 @@ export class ReviewOrchestrator {
         gated: policyResult.gated.length,
         dropped: policyResult.dropped.length,
       });
+
+      // ── 审查成功：保存审查快照 ref ──────────────────────────────────
+      if (run.eventType === 'pull_request' && run.prNumber && targetSha) {
+        try {
+          await this.localRepoManager.saveReviewedRef(
+            repoPaths!.mirrorPath,
+            run.prNumber,
+            run.baseSha!,
+            targetSha
+          );
+        } catch (refError) {
+          logger.warn('保存审查快照 ref 失败（非致命）', {
+            runId: run.id,
+            error: refError instanceof Error ? refError.message : String(refError),
+          });
+        }
+      }
     } catch (error) {
       await this.store.addStep({
         runId: run.id,