diff --git a/app.py b/app.py
index e65f4c8..e94d3c7 100644
--- a/app.py
+++ b/app.py
@@ -914,8 +914,6 @@ def export_certificate_view(cert_id):
             with open(cert['key_path'], 'r') as f:
                 pem_content += f.read()
 
-            from io import StringIO
-            from flask import Response
             return Response(
                 pem_content,
                 mimetype="application/x-pem-file",
@@ -924,32 +922,33 @@ def export_certificate_view(cert_id):
                 }
             )
         elif format_type == 'pem_separate':
-            # 创建临时zip文件包含两个单独的文件
-            import zipfile
-            from io import BytesIO
-
             # 创建内存中的zip文件
             memory_file = BytesIO()
-            with zipfile.ZipFile(memory_file, 'w') as zf:
-                # 添加证书文件
-                with open(cert['cert_path'], 'r') as f:
-                    cert_content = f.read()
-                zf.writestr(f"{cert['common_name']}.crt", cert_content)
 
-                # 添加私钥文件
-                with open(cert['key_path'], 'r') as f:
-                    key_content = f.read()
-                zf.writestr(f"{cert['common_name']}.key", key_content)
+            try:
+                with zipfile.ZipFile(memory_file, 'w', zipfile.ZIP_DEFLATED) as zf:
+                    # 添加证书文件
+                    with open(cert['cert_path'], 'r') as f:
+                        cert_content = f.read()
+                    zf.writestr(f"{cert['common_name']}.crt", cert_content)
 
-            memory_file.seek(0)
+                    # 添加私钥文件
+                    with open(cert['key_path'], 'r') as f:
+                        key_content = f.read()
+                    zf.writestr(f"{cert['common_name']}.key", key_content)
 
-            return Response(
-                memory_file,
-                mimetype="application/zip",
-                headers={
-                    "Content-Disposition": f"attachment; filename={cert['common_name']}_separate.zip"
-                }
-            )
+                memory_file.seek(0)
+
+                return Response(
+                    memory_file.getvalue(),
+                    mimetype="application/zip",
+                    headers={
+                        "Content-Disposition": f"attachment; filename={cert['common_name']}_separate.zip"
+                    }
+                )
+            except Exception as e:
+                flash(f'创建ZIP文件失败: {str(e)}', 'danger')
+                return redirect(url_for('export_certificate_view', cert_id=cert_id))
         else:
             flash('不支持的导出格式', 'danger')