在template\default\forum\viewthread.htm里查找(大概在196行附近)
<!--{if $threadsorts && $_G['forum_thread']['sortid']}--> <a href="forum.php?mod=forumdisplay&fid=$_G[fid]&filter=sortid&sortid=$_G[forum_thread][sortid]">[{$_G['forum']['threadsorts']['types'][$_G['forum_thread']['sortid']]}]</a> <!--{/if}-->
删除以上代码即可