Aiming at the load balancing problem caused by the imbalance of resource utilization of heterogeneous nodes in data center, this study proposes a virtual machine dynamic migration selection strategy based on dynamic threshold-based migration timing decision algorithm and load type perception-based selection algorithm. This strategy first dynamically adjusts the state threshold by monitoring the global load and the proportion of the high and low load nodes, and combines this threshold and load evaluation value to determine the migration timing. Then this strategy analyzes the virtual machine load type, selects the VM to be migrated based on the dependency of the virtual machine and the node resources, the current memory bandwidth ratio of the virtual machine, and the contribution of the virtual machine, and selects the destination node according to the resource matching degree and the migration cost of the virtual machine and the destination node. Thereby this strategy implements dynamic adjustment of virtual machines for high-load and low-load nodes to optimize node resource allocation. The experimental results show that this strategy can effectively reduce the number of virtual machine migrations and ensure the quality of data center services, and ultimately improve the load balancing ability of the data center.