MPI is the most important parallel programming tool in cluster currently. It implements communication in parallel program by message. Implementing load balance in MPI parallel program is very important. It may reduce running time and improve performance of MPI parallel program, aiming at solving the dynamic balancing problem in homogeneous cluster system. This paper proposes an implementing method in MPI parallel program that can transfer tasks between nodes effectively by nodepsilas load. The experiments prove the availability and practicability of the algorithm in parallel computing task.