Abstract: To solve system performance problems caused by extreme heterogeneity and churn in DHT-based P2P system,a new P2P system based on Chord and named RR-Chord is proposed.In RR-Chord all nodes are divided into routing peers and non-routing peers.Routing peers have more sources and more routing information.Routing peers can adjust the size of finger table dynamically.All the routing peers form a routing-ring.All lookup requests are routed on the routing-ring to improve the lookup performance.In addition,to further decrease the maintenance cost caused by churn,a new join algorithm is designed.Theoretical analysis and simulations showed that RR-Chord drastically improves the routing performance and greatly decreases the maintenance overhead.