Abstract: Cloud storage possesses enormous advantages: ubiquitous access, high reliability and scalability and so on. But, unfortunately, also several security risks such as sensitive data disclosure, unauthorized access and data integrity etc are still existing. Aiming at the problem of sensitive data disclosure, an efficient linear homomorphic encryption scheme from R-LWE is proposed in this paper. In this scheme, the data is encrypted first and then stored in cloud in a distributed manner, and its security is based on the difficulty of R-LWE problem. The analyses indicate that the efficiency of the proposed scheme is much more efficient than the additive homomorphic encryption scheme from LWE, and it is secure under chosen plaintext attacks (CPA) in standard model. Finally, the architecture of privacy protection of cloud storage based on the proposed scheme is introduced in this paper.