The invention discloses a method and a system of implementing an HTTP (Hyper Text Transport Protocol) cache. The system comprises a user terminal, a Local DNS (Domain Name Server), a DPI (Data Processing Installation) system, a DNS redirect server, an ICP (Internet Content Provider) DNS server and a cache server, wherein through starting using and monitoring a timer, if only a DNS resolution result fed back by the DNS redirect server is guaranteed to be received in a valid time bucket of T2-T1, a user can be guaranteed to use the cache, thereby avoiding the problems that the existing DNS hijack scheme replies the DNS resolution result more early in the ICP DNS server than in the DNS redirect server, and then the cache is unable to serve the user of a home network, and through TTL (Time To Live) advanced iterative query and cache refresh mechanisms, effective duration of the resolution result of the cache in the Local DNS server is implemented, the problem that the user needs to wait DNS query in a DNS query process to generate time delay is avoided, user perception is greatly improved and system efficiency is improved.