This article is designed to solve the problem of system load imbalance and low efficiency introduced by massive parallel tasks running on some heavy nodes in the Cloud Computing environment. This study proposes a load balancing algorithm based on virtual machine migration which includes load balancing architecture, load gathering, load monitoring, load forecasting, migration trigger time, source machine selecting and etc. Experimental results based on the CloudSim tool reveal that the algorithm can guarantee load balancing and improve the performance of the system.