With the rapid development of cloud computing, physical resources of the cloud data centers have been increasing and how to improve the utilization of server resources is an important research direction. The virtual machine migration method proposed in this paper achieves the reallocation of server hardware resources by migrating the virtual machines between servers in order to realize the resource scheduling and improve the resource utilization. The proposed method solves the problems that how to determine the trigger condition of virtual machine migration, select the target virtual machine and choose the destination node. The experimental results show that the proposed method can improve the utilization of server resources under the cloud computing environment effectively.