这是因为当你保存帖子时，WordPress会打电话给你sanitize_title 函数来清理标题。此功能适用sanitize_title 滤器

一个用于sanitize_title 筛选器为sanitize_title_with_dashes 函数，该函数通过调用seems_utf8 函数，如果标题具有utf8格式，则函数调用utf8_uri_encode 作用

utf8_uri_encode 函数接收两个参数：$utf8_string 和$length. 第一个参数是标题，第二个参数是长度，标题不应溢出。

sanitize_title_with_dashes 函数传递标题，长度限制为200个字符。因此，如果要更改限制，必须更改sanitize_title 滤器现在我们来讨论一个有点脏的解决方案，但它应该可以帮助您：

// first of all lets remove standard hook
remove_filter( \'sanitize_title\', \'sanitize_title_with_dashes\' );

// add our custom hook 
add_filter( \'sanitize_title\', \'wpse8170_sanitize_title_with_dashes\', 10, 3 );
function wpse8170_sanitize_title_with_dashes( $title, $raw_title = \'\', $context = \'display\' ) {
    $title = strip_tags($title);
    // Preserve escaped octets.
    $title = preg_replace(\'|%([a-fA-F0-9][a-fA-F0-9])|\', \'---$1---\', $title);
    // Remove percent signs that are not part of an octet.
    $title = str_replace(\'%\', \'\', $title);
    // Restore octets.
    $title = preg_replace(\'|---([a-fA-F0-9][a-fA-F0-9])---|\', \'%$1\', $title);

    if (seems_utf8($title)) {
        if (function_exists(\'mb_strtolower\')) {
            $title = mb_strtolower($title, \'UTF-8\');
        }
        $title = utf8_uri_encode($title, 1000); // <--- here is the trick!
    }

    $title = strtolower($title);
    $title = preg_replace(\'/&.+?;/\', \'\', $title); // kill entities
    $title = str_replace(\'.\', \'-\', $title);

    if ( \'save\' == $context ) {
        // Convert nbsp, ndash and mdash to hyphens
        $title = str_replace( array( \'%c2%a0\', \'%e2%80%93\', \'%e2%80%94\' ), \'-\', $title );

            // Strip these characters entirely
            $title = str_replace( array(
            // iexcl and iquest
            \'%c2%a1\', \'%c2%bf\',
            // angle quotes
            \'%c2%ab\', \'%c2%bb\', \'%e2%80%b9\', \'%e2%80%ba\',
            // curly quotes
            \'%e2%80%98\', \'%e2%80%99\', \'%e2%80%9c\', \'%e2%80%9d\',
            \'%e2%80%9a\', \'%e2%80%9b\', \'%e2%80%9e\', \'%e2%80%9f\',
            // copy, reg, deg, hellip and trade
            \'%c2%a9\', \'%c2%ae\', \'%c2%b0\', \'%e2%80%a6\', \'%e2%84%a2\',
            // grave accent, acute accent, macron, caron
            \'%cc%80\', \'%cc%81\', \'%cc%84\', \'%cc%8c\',
        ), \'\', $title );

        // Convert times to x
        $title = str_replace( \'%c3%97\', \'x\', $title );
    }

    $title = preg_replace(\'/[^%a-z0-9 _-]/\', \'\', $title);
    $title = preg_replace(\'/\\s+/\', \'-\', $title);
    $title = preg_replace(\'|-+|\', \'-\', $title);
    $title = trim($title, \'-\');

    return $title;
}