diff --git a/apps/em/cd.py b/apps/em/cd.py
index 5b10f12f..44779f1e 100644
--- a/apps/em/cd.py
+++ b/apps/em/cd.py
@@ -12,9 +12,15 @@ def get_tyy_data(*args):
     resp = sc.recv(1024)
     if len(resp) < 8:
         raise ParseError("设备未启动")
-    json_data = resp[5:-4]
-    json_str = json_data.decode('utf-8')
-    return json.loads(json_str)
+    try:
+        json_data = resp[5:-4]
+        json_str = json_data.decode('utf-8')
+        res = json.loads(json_str)
+    except Exception:
+        raise
+    finally:
+        sc.close()
+    return res
 
 if __name__ == '__main__':
     print(get_tyy_data())
\ No newline at end of file