The invention discloses an instant messaging method based on distributed cache. The method includes the steps: reading a configuration file by cache proxy middleware to learn cluster addresses with different classifications, and accessing corresponding clusters by the cache proxy middleware according to the content information requested cache obtain cache information; acquiring cluster addresses by the middleware when data are added, and submitting the cluster addresses to corresponding cluster cache data; performing classification cluster processing on a Redis according to stored contents, enabling the Redis to start a clustering function, setting a plurality of redis cases into clusters according to the classifications of the cache data, and enabling each cluster to separately cache same data. The method solves the problems of reduction of hit rate and reduction of server performance caused by increase of single cache services along with increase of data volume, and communication efficiency is improved.