Abstract: Rapid developments of distributed systems，networking technologies，and multi-media technologies are bringing us a possibility to access remote huge-media-data on-line.Distributed Media Service System becomes hot topic of current researches and developments.One of the great challenges in VoD domain is to optimize the performance/cost ratio of the designed systems.In this paper，the design and implementation of a clustered，high performance，high availability and low cost VoD system—CVoD is presents，which is based on a network of PC.Through the experimental test of the prototype of CVoD，CVoD succeeds to server 90 near DVD quality streams per node，having great potentials for further expanding.With the scaling of CVoD，the results of our experimental test prove the linear relationship between the number of server nodes and the number of served streams that can be concurrently serviced by CVoD.The main inhibitory factor for further expanding of the system is the network bandwidth.The results of experimental test prove that CVoD has good performance expandability and high availability.