If you do not know the encoding format of the string, you can check the character as follows: $encode = mb_detect_encoding ($string array (” ASCII, ”’ UTF - 8 ’,” GB2312 ’, “GBK”, ‘BIG5’)); echo $encode; So we know what it’s coded for. Subsequent operations can also transcode it: if ($encode = = “UTF - 8”) { $string = iconv (” UTF - 8 ”, “GBK”, $string); }