diff --git a/httprunner/report.py b/httprunner/report.py
index 37decadf..cc8e38c6 100644
--- a/httprunner/report.py
+++ b/httprunner/report.py
@@ -153,12 +153,6 @@ def __stringify_request(request_data):
     """
     for key, value in request_data.items():
 
-        if key == "body":
-            try:
-                value = json.loads(value)
-            except JSONDecodeError:
-                pass
-
         if isinstance(value, (list, dict)):
             value = dumps_json(value)
 
@@ -169,6 +163,13 @@ def __stringify_request(request_data):
             except UnicodeDecodeError:
                 pass
 
+            if key == "body":
+                try:
+                    # request body is in json format
+                    value = json.loads(value)
+                except JSONDecodeError:
+                    pass
+
         elif not isinstance(value, (basestring, numeric_types, Iterable)):
             # class instance, e.g. MultipartEncoder()
             value = repr(value)