A new routing algorithm of peer-to-peer file sharing system with routing indices was proposed, in which a node forwards a query to neighbors that are more likely to have answers based on its statistics. The proposed algorithm was tested by creating a P2P simulator and varying the input parameters, and was compared to the search algorithms using flooding (FLD) and random walk (RW). The result shows that with the proposed design, the queries are routed effectively, the network flows are reduced remarkably, and the peer-to-peer file sharing system gains a good expansibility.