WordPress中沒有本地方法可以做到這一點。原因是標簽不依賴于類別，它們是分開的。話雖這么說，要使某個特定類別的所有標簽都在使用中，唯一的方法是循環瀏覽該類別的每個帖子并獲取每個帖子的標簽。

• 原文來源：詳情

我已經編寫了一個快速功能來做到這一點。

（包括子類別和帖子中的所有標簽）

將此函數放入您的functions.php文件中。

function get_tags_in_use($category_ID, $type = 'name'){
    // Set up the query for our posts
    $my_posts = new WP_Query(array(
      'cat' => $category_ID, // Your category id
      'posts_per_page' => -1 // All posts from that category
    ));

    // Initialize our tag arrays
    $tags_by_id = array();
    $tags_by_name = array();
    $tags_by_slug = array();

    // If there are posts in this category, loop through them
    if ($my_posts->have_posts()): while ($my_posts->have_posts()): $my_posts->the_post();

      // Get all tags of current post
      $post_tags = wp_get_post_tags($my_posts->post->ID);

      // Loop through each tag
      foreach ($post_tags as $tag):

        // Set up our tags by id, name, and/or slug
        $tag_id = $tag->term_id;
        $tag_name = $tag->name;
        $tag_slug = $tag->slug;

        // Push each tag into our main array if not already in it
        if (!in_array($tag_id, $tags_by_id))
          array_push($tags_by_id, $tag_id);

        if (!in_array($tag_name, $tags_by_name))
          array_push($tags_by_name, $tag_name);

        if (!in_array($tag_slug, $tags_by_slug))
          array_push($tags_by_slug, $tag_slug);

      endforeach;
    endwhile; endif;

    // Return value specified
    if ($type == 'id')
        return $tags_by_id;

    if ($type == 'name')
        return $tags_by_name;

    if ($type == 'slug')
        return $tags_by_slug;
}

然后，當您要獲取特定類別的標簽時，請像下面這樣調用此函數：

// First paramater is the category and the second paramater is how to return the tag (by name, by id, or by slug)
// Leave second paramater blank to default to name

$tags = get_tags_in_use(59, 'name');

希望這可以幫助。

編輯：

這是您需要與其他功能結合使用的功能：

function tag_cloud_by_category($category_ID){
    // Get our tag array
    $tags = get_tags_in_use($category_ID, 'id');

    // Start our output variable
    echo '<div class="tag-cloud">';

    // Cycle through each tag and set it up
    foreach ($tags as $tag):
        // Get our count
        $term = get_term_by('id', $tag, 'post_tag');
        $count = $term->count;

        // Get tag name
        $tag_info = get_tag($tag);
        $tag_name = $tag_info->name;

        // Get tag link
        $tag_link = get_tag_link($tag);

        // Set up our font size based on count
        $size = 8 + $count;

        echo '<span style="font-size:'.$size.'px;">';
        echo '<a href="'.$tag_link.'">'.$tag_name.'</a>';
        echo ' </span>';

    endforeach;

    echo '</div>';
}

因此，您可以像下面這樣簡單地使用此功能：

tag_cloud_by_category($cat_id);