With the development of society, the total amount of library is orders of magnitude increase, people faced a large number of books and literature don’t know how to choice, and the traditional book retrieval technology is not to provide readers with the active and personalized search results. Recommendation system is an intelligent system, it is the user to the target object selection, evaluation of large amounts of information through specific algorithms for processing, according to the processing results in the formation of recommendation list is recommended to the user, in order to provide decision-making reference. This article will study and discuss the collaborative filtering recommendation system based on classification.