代码方面来自知更鸟博客： https://zmingcx.com/redirect-wordpress-registration-page-custom-registration-page.html

具体代码如下：

add_filter( 'register','zm_register_url' );
function zm_register_url($link){
	// 更改注册链接
	return str_replace( site_url('wp-login.php?action=register', 'login' ),site_url( 'register', 'login' ),$link );
}
 
add_filter( 'site_url', 'zm_fix_register_urls', 10, 3 );
function zm_fix_register_urls( $url, $path, $orig_scheme ){
	// 替换注册链接
	if ( $orig_scheme !== 'login' )
	return $url;
 
	if ($path == 'wp-login.php?action=register')
	return site_url('register', 'login');
	return $url;
}