Distributed storage system has been widely used currently. Compared with traditional NAS and SAN storage, distributed storage system has obvious advantages in terms of cost, performance and security. The security of distributed storage system is mainly reflected in the data redundancy level. However, if there are security risks in the operating system and network environment, the security of the data still cannot be guaranteed. How to fundamentally solve the security risks of distributed storage system is an urgent problem. Based on the theory of mimic defense, Storage Architecture for Mimic Defense(SAMD) is put forward in this paper. In the proposed SAMD, dynamic heterogeneous redundancy function is introduced into distributed storage system. During the process of data reading and writing, the execution results are obtained from dynamic heterogeneous executive units, and the processing and judgement are carried out according to the customized strategy. It then dynamically allocates the executive units and storage nodes to achieve the effect of active defense.