使用get_comments( $args ) 获取帖子的所有评论。

$args= array(
    \'author_email\' => \'\',
    \'ID\' => \'\',
    \'karma\' => \'\',
    \'number\' => \'\',
    \'offset\' => \'\',
    \'orderby\' => \'\',
    \'order\' => \'DESC\',
    \'parent\' => \'\',
    \'post_id\' => 0,
    \'post_author\' => \'\',
    \'post_name\' => \'\',
    \'post_parent\' => \'\',
    \'post_status\' => \'\',
    \'post_type\' => \'\',
    \'status\' => \'\',
    \'type\' => \'\',
    \'user_id\' => \'\',
    \'search\' => \'\',
    \'count\' => false,
    \'meta_key\' => \'\',
    \'meta_value\' => \'\',
    \'meta_query\' => \'\');

$comments = get_comments(array(\'post_id\'=> \'your post id\'));
$comment_ids = array();
foreach($comments as $comment):
    $comment_ids[] = $comment->comment_ID;
endforeach;
print_r(comment_ids);