将此方法放到Thinkphp/Common/function.php里
/*
 * 字符串截取函数
 * 大白驴 
 * 2016-11-29
   qq 675835721
 * */

function msubstr($str, $start=0, $length, $charset="utf-8", $suffix=true)
{
    if(function_exists("mb_substr")){
        if($suffix)
            return mb_substr($str, $start, $length, $charset)."...";
        else
            return mb_substr($str, $start, $length, $charset);
    }
    elseif(function_exists(‘iconv_substr‘)) {
        if($suffix)
            return iconv_substr($str,$start,$length,$charset)."...";
        else
            return iconv_substr($str,$start,$length,$charset);
    }
    $re[‘utf-8‘]   = "/[x01-x7f]|[xc2-xdf][x80-xbf]|[xe0-xef]
                  [x80-xbf]{2}|[xf0-xff][x80-xbf]{3}/";
    $re[‘gb2312‘] = "/[x01-x7f]|[xb0-xf7][xa0-xfe]/";
    $re[‘gbk‘]    = "/[x01-x7f]|[x81-xfe][x40-xfe]/";
    $re[‘big5‘]   = "/[x01-x7f]|[x81-xfe]([x40-x7e]|xa1-xfe])/";
    preg_match_all($re[$charset], $str, $match);
    $slice = join("",array_slice($match[0], $start, $length));
    if($suffix) return $slice."…";
    return $slice;
}

前台截取

<p class="pb10">{$s1.product_standard|msubstr=0,10,‘utf-8‘,false}</p>

Thinkphp 3.2中字符串截取