复制下面的代码粘贴到网站主题函数functions.php里面。

/*
* WordPress注册邮箱白名单 ‎
*/
function is_valid_email_domain($login, $email, $errors ){
$valid_email_domains = array("163.com","yeah.net","b0ae.cn","qq.com");// 允许注册的邮箱信息
$valid = false;
foreach( $valid_email_domains as $d ){
$d_length = strlen( $d );
$current_email_domain = strtolower( substr( $email, -($d_length), $d_length));
if( $current_email_domain == strtolower($d) ){
$valid = true;
break;
}
}
// if invalid, return error message
if( $valid === false ){
$errors->add('domain_whitelist_error',__( '<strong>ERROR</strong>: 目前仅支持QQ邮箱注册。' ));
}
}
add_action('register_post', 'is_valid_email_domain',10,3 );