I have written a php code to solve the problem.
[code]
<?php
$uri = $_SERVER['REQUEST_URI'];
$qs = $_SERVER['QUERY_STRING'];
$uri = strtok($uri, '?');
$qs = $_SERVER['QUERY_STRING'] = strtok('?');
parse_str($qs, $qs_arr);
$_REQUEST = array_merge($_REQUEST, $qs_arr);
[/code]

My blog post here: http://seaprince.cn/nginx-query_string-bug/