Abstract: A grid-based cooperative caching system called GCaching is proposed in this paper.GCaching organizes a set of distributed caching proxy servers to form a “caching pool”.The proxy servers cooperate and make full use of each other’s cache to gain better system performance.In GCaching, a novel GCPR algorithm is designed to place and replace caching objects in large-scale distributed caches.GCPR can organize cache data adapting to user request patterns.Simulation experiments show that GCPR has higher hit rate and fewer visit hops than traditional algorithms such as LRU.