For traditional client-server streaming service pattern, a centralized multimedia stream server serves client?s requests. But with the increasing popularity of streaming applications, this pattern introduces new challenges over best-effort network: high latency and loss rates can not provide good quality audio/video streaming to client, centralized server has a limit on delivering many simultaneously streams, the same stream sessions can not share data between each other. To address these issues, we deploy a streaming proxy server close to client to cache media objects in memory and disk to reduce the network traffic, the server load and the data delivery latency. In this paper, we propose a novel cache of streaming proxy server based on cluster architecture. In particular, Dynamic Shared Running Memory Cache (DSRMC), network prefetch and cache admission policy are integrated in streaming caching design. Simulation results demonstrate the effectiveness of this novel cache.