您可以使用$wp_taxonomies 已经我只是把它写了下来，所以您可能需要尝试一下，以启动并运行以下代码行，但它应该让您了解它应该如何工作（将其视为参考/伪代码）：

编辑：在来自的注释之后Mike Schinkel 我更新了代码，以便更容易忽略内置分类法（请参阅：\\u builtin）。我希望Mike在这里发布他发给我的示例，这样他的（更简单的）解决方案可以标记为最终方法。。。

// equals the following $keys
$wp_taxonomies[\'category\'] == $wp_taxonomies[0];
$wp_taxonomies[\'post_tag\'] == $wp_taxonomies[1];
$wp_taxonomies[\'nav_menu\'] == $wp_taxonomies[2];
$wp_taxonomies[\'link_category\'] == $wp_taxonomies[3];

// after $key #3 you retrieve all different registered taxonomies
$all_tax = count($wp_taxonomies)-4; // gives you the amount of reg. tax.

// Here starts the actual code
$post_types = array(); // some empty array to save your post types for further procesing
$i = 0;
foreach ( $wp_taxonomies as $tax ) {
if ( !$tax->_builtin)
  $post_type_arr = $tax[$i]->object_type; // array of post types in the current taxonomy
  foreach ( $post_type_arr as $arr ) : // loop through all post types assigned to the taxonomy
    $post_types[] .= $arr; // assign them to our array of post types
  endforeach;
  $i++;
}
$post_types = array_unique($post_types); // drop doublettes out of the array
var_dump($post_types);

# expected result close to this...

# Array(
#   1 => $post_type_a,
#   2 => $post_type_b,
#   3 => $post_type_n
# );

这就是真正的解决方案：

function get_object_types_unique( $all_r_custom = false ) {
    $tax_object = get_taxonomies( array( \'_builtin\' => $all_r_custom ), \'objects\' );
    if ( $all_r_custom == true )
        $tax_object = array_merge( $tax_object, get_taxonomies( array( \'_builtin\' => false ), \'objects\' ) );

    $object_types = array();
    foreach ( $tax_object as $tax ) {
        $object_types = array_merge( $object_types, $tax->object_type );
    }

    $object_types = array_unique( $object_types );
    return $object_types;
}