Cloud computing is a term that used for distributed computing, on a network. It is meant network-based services that these services are provided through virtual ISPs. Most of the old virtual machine migration techniques concentrated on the migration of a single virtual machine. These techniques are insufficient, when the whole virtual cluster needs to be migrated. In these methods, data replication in each round leads to many computational overheads.In this paper, a method is proposed for virtual machine migration from one data center to another. The proposed method uses the greedy algorithm for virtual machine selection. Virtual machines within a cluster are given priority, which reduces the total migration time of a cluster. This method is simulated in CloudSim tools in Eclipse. Simulation results show that the bandwidth parameter has the important role in the virtual machine migration.