您可以使用ACF plugin 对于https://wordpress.org/plugins/advanced-custom-fields/.

需要执行的步骤：

下载并安装ACF插件Custom Fields 左侧菜单中的链接将自定义字段添加为：functions.php 文件名：

function acf_load_color_field_choices( $field ) {    
    // reset choices
    $field[\'choices\'] = array();
  $blogusers = get_users();
  $field[\'choices\'][0] = "Select User";
  foreach($blogusers as $user){
            // append to choices
            $field[\'choices\'][ $user->ID ] = $user->display_name;
    }
    // return the field
    return $field;    
}
add_filter(\'acf/load_field/name=select_user_for_post\', \'acf_load_color_field_choices\');

1. get user list

2. Dynamically populate a select field’s choices