Abstract: Through analyzing Internet cache protocol （ICP） and cooperative web caching system based on concentrated management （CMCS）, a domain distributed cooperative web caching system model is proposed. It solves the problem of the duplicates among proxies in ICP and the frailty of CMCS, and sufficiently considers the processing and caching ability of each proxy cache. Using the interval discretization and weighted allocating interval piece algorithm, the tasks are evenly and rationally distributed to every proxies. Compared with ICP and CMCS, the model optimizes the structure of the system and improves the system performance as well.