要避免递归，你应该检查的请求线，而不是的如％{QUERY_STRING} 可能已经被另一个规则已经改变的查询字符串：

To avoid recursion, you should check the request line instead as the query string in %{QUERY_STRING} may already have been changed by another rule:

RewriteCond %{THE_REQUEST} ^GET\ /\?(([^&\s]*&)*)tag=([^&\s]+)&?([^\s]*)
RewriteRule ^(.*)$ /tag/%3?%1%4 [L,R=301]

然后你可以重写请求回内部没有矛盾：

Then you can rewrite that requests back internally without conflicts:

RewriteRule ^tag/(.*) index.php?tag=$1 [L]