Many organizations nowadays operate local area networks connecting hundreds of workstations and personal computers and use them as a cluster system. Dynamic load balancing is an important method to improve the performance on such heterogeneous system. Diffusion algorithm is a dynamic load balancing method for homogeneous system. In this paper, the diffusion algorithm is extended to heterogeneous system, the influence of the arrangement of different processors in the system on the convergence rate of the diffusion algorithm is studied, and an optimal method is proposed to improve the convergence rate. Primary result shows that it can find the better arrangement of the processors to accelerate the diffusion algorithm.