这是我在一个项目中创建的代码。其中，您应该将您的CPT名称注册为“产品”。因此，创建的分类仅对您的CPT产品可见。在函数中添加这些代码。php文件。它很简单，不需要插件。

/* Link products CPT to categories taxonomy
*/
add_action( \'init\', \'add_category_taxonomy_to_products\' );
function add_category_taxonomy_to_products() {
    register_taxonomy_for_object_type( \'category\', \'products\' ); // CPT as products
}

//Adding taxonomies for custom post type products
function create_products_taxonomies() {
    $labels = array(
        \'name\'              => _x( \'Products Categories\', \'taxonomy general name\' ),
        \'singular_name\'     => _x( \'Category\', \'taxonomy singular name\' ),
        \'search_items\'      => __( \'Search Categories\' ),
        \'all_items\'         => __( \'All Categories\' ),
        \'parent_item\'       => __( \'Parent Category\' ),
        \'parent_item_colon\' => __( \'Parent Category:\' ),
        \'edit_item\'         => __( \'Edit Category\' ),
        \'update_item\'       => __( \'Update Category\' ),
        \'add_new_item\'      => __( \'Add New Category\' ),
        \'new_item_name\'     => __( \'New Category Name\' ),
        \'menu_name\'         => __( \'Categories\' ),
    );

    $args = array(
        \'hierarchical\'      => true, // Set this to \'false\' for non-hierarchical taxonomy (like tags)
        \'labels\'            => $labels,
        \'show_ui\'           => true,
        \'show_admin_column\' => true,
        \'query_var\'         => true,
        \'rewrite\'           => array( \'slug\' => \'categories\' ),
    );

    register_taxonomy( \'products_categories\', array( \'products\' ), $args );
    flush_rewrite_rules() ;
}
add_action( \'init\', \'create_products_taxonomies\', 0 );