diff --git a/backend/run_server.py b/backend/run_server.py
index f2acf23..f10830c 100644
--- a/backend/run_server.py
+++ b/backend/run_server.py
@@ -44,40 +44,40 @@ def apply_config_to_env(config: dict) -> None:
     if "port" in backend_config:
         os.environ.setdefault("BACKEND_PORT", str(backend_config["port"]))
 
-    # Database configuration
+    # Database configuration - use direct assignment to ensure config values are used
     db_config = backend_config.get("database", {})
     if "host" in db_config:
-        os.environ.setdefault("DB_HOST", db_config["host"])
+        os.environ["DB_HOST"] = db_config["host"]
     if "port" in db_config:
-        os.environ.setdefault("DB_PORT", str(db_config["port"]))
+        os.environ["DB_PORT"] = str(db_config["port"])
     if "user" in db_config:
-        os.environ.setdefault("DB_USER", db_config["user"])
+        os.environ["DB_USER"] = db_config["user"]
     if "password" in db_config:
-        os.environ.setdefault("DB_PASS", db_config["password"])
+        os.environ["DB_PASS"] = db_config["password"]
     if "database" in db_config:
-        os.environ.setdefault("DB_NAME", db_config["database"])
+        os.environ["DB_NAME"] = db_config["database"]
     if "poolSize" in db_config:
-        os.environ.setdefault("DB_POOL_SIZE", str(db_config["poolSize"]))
+        os.environ["DB_POOL_SIZE"] = str(db_config["poolSize"])
 
-    # External API configuration
+    # External API configuration - use direct assignment
     api_config = backend_config.get("externalApis", {})
     if "authApiUrl" in api_config:
-        os.environ.setdefault("AUTH_API_URL", api_config["authApiUrl"])
+        os.environ["AUTH_API_URL"] = api_config["authApiUrl"]
     if "difyApiUrl" in api_config:
-        os.environ.setdefault("DIFY_API_URL", api_config["difyApiUrl"])
+        os.environ["DIFY_API_URL"] = api_config["difyApiUrl"]
     if "difyApiKey" in api_config:
-        os.environ.setdefault("DIFY_API_KEY", api_config["difyApiKey"])
+        os.environ["DIFY_API_KEY"] = api_config["difyApiKey"]
     if "difySttApiKey" in api_config:
-        os.environ.setdefault("DIFY_STT_API_KEY", api_config["difySttApiKey"])
+        os.environ["DIFY_STT_API_KEY"] = api_config["difySttApiKey"]
 
-    # Authentication configuration
+    # Authentication configuration - use direct assignment
     auth_config = backend_config.get("auth", {})
     if "adminEmail" in auth_config:
-        os.environ.setdefault("ADMIN_EMAIL", auth_config["adminEmail"])
+        os.environ["ADMIN_EMAIL"] = auth_config["adminEmail"]
     if "jwtSecret" in auth_config:
-        os.environ.setdefault("JWT_SECRET", auth_config["jwtSecret"])
+        os.environ["JWT_SECRET"] = auth_config["jwtSecret"]
     if "jwtExpireHours" in auth_config:
-        os.environ.setdefault("JWT_EXPIRE_HOURS", str(auth_config["jwtExpireHours"]))
+        os.environ["JWT_EXPIRE_HOURS"] = str(auth_config["jwtExpireHours"])
 
     # File configuration - set TEMPLATE_DIR and RECORD_DIR relative to base
     base_dir = get_base_dir()
@@ -116,8 +116,21 @@ def main():
 
     # Load and apply configuration
     config = load_config(args.config)
+
+    # Debug: print loaded config
+    print(f"DEBUG: Config path: {args.config}", flush=True)
+    print(f"DEBUG: Loaded config keys: {list(config.keys())}", flush=True)
+    backend_config = config.get("backend", {})
+    db_config = backend_config.get("database", {})
+    print(f"DEBUG: DB config: host={db_config.get('host')}, user={db_config.get('user')}, pass={'***' if db_config.get('password') else 'EMPTY'}", flush=True)
+
     apply_config_to_env(config)
 
+    # Debug: print env vars after setting
+    print(f"DEBUG: ENV DB_HOST={os.environ.get('DB_HOST')}", flush=True)
+    print(f"DEBUG: ENV DB_USER={os.environ.get('DB_USER')}", flush=True)
+    print(f"DEBUG: ENV DB_PASS={'***' if os.environ.get('DB_PASS') else 'EMPTY'}", flush=True)
+
     # Command line arguments override everything
     if args.host:
         os.environ["BACKEND_HOST"] = args.host