Abstract: In the report， multi-virtual machine migration model in cloud data centers based on group， GBM-VMM， was proposed. During selection of group in GBM-VMM， the effects of the migration time cost between VMs and the extra energy consumption of the VM on the response time of the host were analyzed. According to the resource status of the overloaded PM and the degree of connection of the remaining VMs， the forming of candidate migrates virtual machines. The results of simulation experiment indicated that compared with the other single or multiply VM migration strategies， GBM-VMM improve the characteristics indexes of cloud data center， and provide a good reference for the constructing of other green cloud data center.