Current P2P Web cache is analyzed and a structured P2P-based cooperative web caching system, namely DHTCache, is proposed. The underlying P2P routing mechanism of DHTCache uses SA-Chord and the upper cache positioning mechanism uses the URL-pathed index and lookup scheme. In this way, not only performance problems caused by the heterogeneity among P2P nodes is overcame, but also the characteristics of Web users to access is combined. Simulations show that compared to the previous solutions, DHTCache can achieve better lookup performance.