With the massage passing interface, a parallel solution method was proposed for the simulation of the elliptic mild slope equation, and implemented numerically on a parallel system based on a personal computer cluster, which was constructed by the authors. The wave transformations over two typical topographies with mild slopes were simulated. Numerical results show that the parallel solution method presented in this paper can not only increase the computational efficiency, but also decrease very much the memory storage on a single computer, so the parallel system based on a PCC can be used to simulate wave transformations over much larger areas.