http://goo.gl/FGVof6

    //Author： [email protected]
    function chineseToUnicode($str){
        //split word
        preg_match_all('/./u',$str,$matches);

        $c = "";
        foreach($matches[0] as $m){
            $c .= "&#".base_convert(bin2hex(iconv('UTF-8',"UCS-4",$m)),16,10);
        }
        return $c;
    }
    //Print result
    $str = "買野 測試 Stackoverflow";
    echo chineseToUnicode($str);