In this work, the migration timing of virtual machines is studied for frequent migration of virtual machine in cloud data centers, an adaptive migration trigger method of virtual machine based on improved exponential smoothing prediction is proposed. A combination of dual threshold and prediction is applied to the strategy. First, the load prediction is triggered by continuously determining the load state. Then, the host load state at the next moment is adaptively predicted based on the historical load value, and finally the virtual machine migration is triggered. This method not only achieves host load balancing, but also improves migration efficiency and reduces energy consumption. Experiments show that the method reduces the energy consumption and the number of migration by about 7.34% and 58.55% respectively, which has sound optimization effect.