Traditional packet classification for IPv4involves examining standard 5-tuple of a packet header,source address,destination address,source port,destination port and protocol.With introduction of IPv6 flow label field which entails labeling the packets belonging to the same flow,packet classification can be resolved based on 3dimensions:flow label,source address and destination address.In this paper,we propose a novel approach for the 3-tuple packet classification based on flow label.Besides,by introducing a conversion engine to covert the source-destination pairs to the compound address prefixes,we put forward an algorithm called Reducing Dimension (RD) with dimension reduction capability,which combines heuristic tree search with usage of buckets.And we also provide an improved version of RD,called Improved RD (IRD),which uses two mechanisms:path compression and priority tag,to optimize the performnce.To evaluate our algorithm,extensive experiments have been conducted using a number of synthetically generated databases.For the memory consumption,the two proposed new algorithms only consumes around 3％of the existing algorithms when the number of filters increases to 10 k.And for the average search time,the search time of the two proposed algorithms is more than four times faster than others when the number of filters is 10 k.The results show that the proposed algorithm works well and outperforms many typical existing algorithms with the dimension reduction capability.