也许:

curl_setopt($ch, CURLOPT_POSTFIELDS, $_POST);

来自curl_setopt:

这既可以作为 urlencoded 字符串(如 'para1=val1&para2=val2&...')传递，也可以作为以字段名称作为键和字段数据作为值的数组传递.

This can either be passed as a urlencoded string like 'para1=val1&para2=val2&...' or as an array with the field name as key and field data as value.