Abstract: To address the intersecting region of the continuous range queries needs to repeat queries in the location-based service, this paper proposes a method of trajectory privacy protection based on caching candidate result set. The method utilizes two-level cache mechanism to cache user's candidate result set at client and anonymizer, and the next query point on the trajectory can obtain the answer from the cached data, which can reduce the interaction between the user and the server to reduce the risk of user's information exposed to the server. At the same time, we propose the k-anonymity of the mobile location prediction based on the Markov model, which can improve the hit ratio of cache and enhance the user's trajectory privacy. Security analysis shows that the method can effectively protect the user's trajectory privacy. Experiments show this method can reduce the computation and communication overhead of the server.