摘要： 前缀缓存是用来减少互联网上传输量与响应延迟的技术。在前缀缓存技术中，对所有文件固定每次缓存分配空间大小。该文将根据流媒体缓存机理，提出了节省时间比率的概念来表征流媒体缓存系统的播放保障能力，依据时间特性提出了因码率而异的缓存保存方法，来减少固定大小缓存保存方式带来的时间差异量。

关键词: 流媒体；代理服务器；分段缓存；前缀缓存

Abstract: Prefix cache is the major technology of the streaming cache. Most researches on prefix cache concern how to reduce network transfer load.To describe a media request should say how much transfer and how long continuing. This paper concerns about the time character of streaming cache and gives a new cache storage method from point of view of time.

Key words: Streaming media; Proxy server; Segmented cache; Prefix cache