The multigrid method,one of the most efficient iterative algorithm nowadays,possesses of the advantages of fast convergent speed and high accuratcy.Adaptive mesh technique aims at improving the accuracy of prediction by arbitrarily densifying the grids in areas where the gradient of quantities is large.By use of the muti-nested mesh method to speedup the simulation process,adaptive mesh technique is developed with MM5 model to simulate a rainstorm in south of Yangtse River from 17th to 18th June 2002.The result indicate that if the accurucy requirement of convergence is high,the amount of precipitation simulated by adaptive mesh model approaches the observation better than that simulated by uniform mesh model,and the multigrid method can raise the computing efficiency successfully,but if the accurucy requirement of convergence is very low,the multigrid method may be invalidated.