The invention discloses a ciphertext retrieval method based on homomorphic encryption in cloud storage. With the rapid development of cloud computing technology, many users and individuals choose to store local data in the cloud. In this way, the local storage space can be greatly saved. However, faced with a "honest and curious" cloud server, the users would lose control of data, and the efficient retrieval for huge amounts of data on the cloud server has become an urgent problem to be solved. Aimed at this problem, the invention proposes a ciphertext retrieval method based on homomorphic encryption, no information would be revealed to the cloud server and other attackers in the computing process, the security of the data is ensured, meanwhile, a tree structure is used for ciphertext storage so that the ciphertext retrieval is more efficient, and users can be added and deleted dynamically.