diff --git a/autopep8.py b/autopep8.py
index ea63491f..7f9e6967 100755
--- a/autopep8.py
+++ b/autopep8.py
@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 # Copyright (C) 2010-2011 Hideo Hattori
 # Copyright (C) 2011-2013 Hideo Hattori, Steven Myint
 # Copyright (C) 2013-2016 Hideo Hattori, Steven Myint, Bill Wendling
@@ -1286,8 +1284,8 @@ def fix_w504(self, result):
         if m:
             next_line_indent = m.span()[1]
         self.source[line_index + 1] = '{}{} {}'.format(
-                next_line[:next_line_indent], target_operator,
-                next_line[next_line_indent:])
+            next_line[:next_line_indent], target_operator,
+            next_line[next_line_indent:])
 
     def fix_w605(self, result):
         (line_index, _, target) = get_index_offset_contents(result,
@@ -1298,7 +1296,7 @@ def fix_w605(self, result):
             return
         for (pos, _msg) in get_w605_position(tokens):
             self.source[line_index] = '{}r{}'.format(
-                    target[:pos], target[pos:])
+                target[:pos], target[pos:])
 
 
 def get_w605_position(tokens):
@@ -1797,7 +1795,7 @@ def _shorten_line(tokens, source, indentation, indent_word,
 
             second_indent = indentation
             if (first.rstrip().endswith('(') and
-               source[end_offset:].lstrip().startswith(')')):
+                    source[end_offset:].lstrip().startswith(')')):
                 pass
             elif first.rstrip().endswith('('):
                 second_indent += indent_word
@@ -3234,9 +3232,11 @@ def fix_code(source, options=None, encoding=None, apply_config=False):
     """
     options = _get_options(options, apply_config)
 
+    if hasattr(source, 'readlines'):
+        return fix_lines(source.readlines(), options=options)
+
     if not isinstance(source, unicode):
         source = source.decode(encoding or get_encoding())
-
     sio = io.StringIO(source)
     return fix_lines(sio.readlines(), options=options)
 
@@ -4009,6 +4009,11 @@ def wrap_output(output, encoding):
                                       else output)
 
 
+def wrap_input(input, encoding):
+    reader_getter = codecs.getreader(encoding)
+    return reader_getter(input.buffer if hasattr(input, 'buffer') else input)
+
+
 def get_encoding():
     """Return preferred encoding."""
     return locale.getpreferredencoding() or sys.getdefaultencoding()
@@ -4038,12 +4043,24 @@ def main(argv=None, apply_config=True):
         if args.files == ['-']:
             assert not args.in_place
 
-            encoding = sys.stdin.encoding or get_encoding()
+            from lib2to3.pgen2 import tokenize as lib2to3_tokenize
+            if hasattr(sys.stdin, 'buffer'):
+                data = sys.stdin.buffer.read()
+            else:
+                data = sys.stdin.read()
+            bytes_stdin_io = io.BytesIO(data)
+
+            # detect encoding dynamic
+            input_encoding = \
+                lib2to3_tokenize.detect_encoding(bytes_stdin_io.readline)[0]
+            output_encoding = sys.stdin.encoding or get_encoding()
 
+            bytes_stdin_io = io.BytesIO(data)
+            stdin = wrap_input(bytes_stdin_io, input_encoding)
+            stdout = wrap_output(sys.stdout, output_encoding)
             # LineEndingWrapper is unnecessary here due to the symmetry between
             # standard in and standard out.
-            wrap_output(sys.stdout, encoding=encoding).write(
-                fix_code(sys.stdin.read(), args, encoding=encoding))
+            stdout.write(fix_code(stdin, args))
         else:
             if args.in_place or args.diff:
                 args.files = list(set(args.files))
diff --git a/test/suite/windows-gb2312.txt b/test/suite/windows-gb2312.txt
new file mode 100644
index 00000000..4b1934fe
--- /dev/null
+++ b/test/suite/windows-gb2312.txt
@@ -0,0 +1,2 @@
+utf8 = '测试一下gb2312编码'
+print(gbk)
\ No newline at end of file
diff --git a/test/test_gb2312_stdin.py b/test/test_gb2312_stdin.py
new file mode 100644
index 00000000..bd2299cf
--- /dev/null
+++ b/test/test_gb2312_stdin.py
@@ -0,0 +1,21 @@
+import os
+import platform
+import re
+
+def main():
+    os_name  = platform.platform()
+    if not re.match('windows', os_name, flags=re.IGNORECASE):
+        return
+
+    dir_path = os.path.dirname(os.path.abspath(__file__))
+    path = os.path.join(dir_path, 'suite', 'windows-gb2312.txt')
+    print('test old version....')
+    os.system('type %s | autopep8 -' % path)
+
+    print('test new version')
+    autopep8_path = os.path.join(dir_path, '..', 'autopep8.py')
+    os.system('type %s | python %s -' % (path, autopep8_path))
+
+
+if __name__ == "__main__":
+    main()