您可以尝试以下方法，必须在循环中使用：

<?php

// type = comment will only get "real" comments, no ping-/trackbacks
$comments = get_comments(array(\'type\' => \'comment\'));

$threads = 0;
foreach($comments as $comment) {
   // if the comment has no parent, it´s the first of a thread
   if($comment->parent == \'\') { $threads++; }
}  

switch($threads) {
   case 0: echo "There are no comments so far."; break;
   case 1: echo "There is one thread..."; break;
   default: echo "There are \'.$threads.\' comment threads going on."; break;
}

?>