Abstract: The database buffer page replacement algorithm has an important impact in the performance of the database system.Caching is one of the most fundamental metaphor in modern computing，Cache replacement policies play a crucial part in different aspects of today’s high performance computing environments.It studies some of the page replacement algorithms，including the recency based algorithms，the frequency based algorithms and the adaptive algorithms.The LRFU algorithms isn’t a self-tuning algorithm，although it combines the recency and frequency.This paper proposes an improved LRFU algorithm，that can adaptively and dynamically modify the λ value of LRFU.Conducting simulations with a variety of file access patterns and a wide range of buffer size，it shows that the improved LRFU algorithm outperforms a LRFU algorithm in many cases.