当你register your post type, 将子目录添加到has_archive 参数，并作为slug 的参数rewrite 参数：

$args = array(
    // ... other args removed for clarity
    \'rewrite\' => array( \'slug\' => \'subdirectory/custom-post-type\' ),
    \'has_archive\' => \'subdirectory/custom-post-type\',
    // ...
);
register_post_type( \'your_cpt\', $args );