Abstract: Chord protocol is the simplest ring topology of the p2p model with the use of distributed hash table(DHT).In order to improve the lookup efficiency of Chord,many approaches are explored to reduce the average lengths of lookup path to a constant by increasing the routing table size and maintaining too much state information of nodes.It is proposed a regional lookup algorithm based on super-node that addresses these problems.It is shown how to divide the Chord ring into many regions,and located with super-node in a hierarchical way.Results from theoretical analysis and experiments show that the improved lookup algorithm achieves higher efficiency and each node maintains only O(logk) routing information with k regions.