WordPress 4.4以后的版本对中文用户名不友好，所以我借鉴了wp-includes/formatting.php中sanitize_user函数的写法，将以下php代码复制到当前主题目录下的functions.php中，即可让WordPress支持使用中文用户名注册和登录：

function mobantu_sanitize_user ($username, $raw_username, $strict) {
 $username = wp_strip_all_tags( $raw_username );
 $username = remove_accents( $username );
 // Kill octets
 $username = preg_replace( '|%([a-fA-F0-9][a-fA-F0-9])|', '', $username );
 $username = preg_replace( '/&.+?;/', '', $username ); // Kill entities

// 网上很多教程都是直接将$strict赋值false，
 // 这样会绕过字符串检查，留下隐患
 if ($strict) {
 $username = preg_replace ('|[^a-z\p{Han}0-9 _.\-@]|iu', '', $username);
 }

$username = trim( $username );
 // Consolidate contiguous whitespace
 $username = preg_replace( '|\s+|', ' ', $username );

return $username;
 }

add_filter ('sanitize_user', 'mobantu_sanitize_user', 10, 3);

本文转载自模板兔。