This thesis describes a sector-based routing model over structured peer-to-peer networks. According to a predefined system parameter, we divide the key space of structured peer-to-peer network into several sectors. Each sector contains at most one super node and other members in the sector are called local nodes. The results of Simulation show that the routing model dose not only reduces the overhead of maintenance overhead when nodes frequently join or leave in the structured peer-to-peer network, but also improve the performance for lookup.