缓存文档置换机制是电脑处理缓存内存的一种机制。

电脑内存空间的大小固定，无法容纳服务器上所有的文档，所以当有新的文档要被置换入缓存时，必须根据一定的原则来取代掉适当的文档。此原则即所谓缓存文档置换机制。

缓存文档置换方法有：

In computing, cache algorithms (also frequently called cache replacement algorithms or cache replacement policies) are optimizing instructions—​​or algorithms—​​that a computer program or a hardware-maintained structure can follow in order to manage a cache of information stored on the computer. When the cache is full, the algorithm must choose which items to discard to make room for the new ones.