貌似说有利于SEO，有需要的朋友直接copy过去吧，将下面的代码添加到主题文件functions.php中最后一个>之前即可。

/* 自動為文章內的標籤添加內鏈開始 */
$match_num_from = 1;		//一篇文章中同一個標籤少於幾次不自動鏈接
$match_num_to = 1;		//一篇文章中同一個標籤最多自動鏈接幾次
function tag_sort($a, $b){
	if ( $a->name == $b->name ) return 0;
	return ( strlen($a->name) > strlen($b->name) ) ?-1 : 1;
}
function tag_link($content){
	global $match_num_from,$match_num_to;
		$posttags = get_the_tags();
		if ($posttags) {
			usort($posttags, "tag_sort");
			foreach($posttags as $tag) {
				$link = get_tag_link($tag->term_id);
				$keyword = $tag->name;
				$cleankeyword = stripslashes($keyword);
				$url = "<a href=\"$link\" title=\"".str_replace('%s',addcslashes($cleankeyword, '$'),__('View all posts in %s'))."\"";
				$url .= ' target="_blank"';
				$url .= ">".addcslashes($cleankeyword, '$')."</a>";
				$limit = rand($match_num_from,$match_num_to);
				$content = preg_replace( '|(<a[^>]+>)(.*)('.$ex_word.')(.*)(</a[^>]*>)|U'.$case, '$1$2%&&&&&%$4$5', $content);
				$content = preg_replace( '|(<img)(.*)('.$ex_word.')(.*)(>)|U'.$case, '$1$2%&&&&&%$4$5', $content);
				$cleankeyword = preg_quote($cleankeyword,'\'');
				$regEx = '\'(!((<.*)|(<a.*)))('. $cleankeyword . ')(!(([^<>]*)>)|([^>]*</a>))\'s' . $case;
				$content = preg_replace($regEx,$url,$content,$limit);
				$content = str_replace( '%&&&&&%', stripslashes($ex_word), $content);
			}
		}
	return $content;}
add_filter('the_content','tag_link',1);
/* 自動為文章內的標籤添加內鏈結束 */