In recent years, an increasing number of application services are deployed in the cloud. However, the cloud platform faces unknown secu-rity threats brought by its unknown vulnerabilities and backdoors. Many researchers have studied the Cy-ber Mimic Defense (CMD) technologies of the cloud services. However, there is a shortage of tools that enable researchers to evaluate their newly proposed cloud service CMD mechanisms, such as scheduling and decision mechanisms. To fill this gap, we pro-pose MimicCloudSim as a mimic cloud service sim-ulation system based on the basic functionalities of CloudSim.MimicCloudSim supports the simulation of dynamic heterogeneous redundancy (DHR) structure which is the core architecture of CMD technology, and provides an extensible interface to help researchers implement new scheduling and decision mechanisms. In this paper, we firstly describes the architecture and implementation of MimicCloudSim, and then dis-cusses the simulation process. Finally, we demonstrate the capabilities of MimicCloudSim by using a deci-sion mechanism. In addition, we tested the perfor-mance of MimicCloudSim, the conclusion shows that MimicCloudSim is highly scalable.