Adaptive mesh technique is based on the variation method and it aims at improving the accuracy of prediction by arbitrarily densifying the grids in areas where the gradient of numerical solutions is large.By use of the multi-nested mesh method to speedup the simulation process,adaptive mesh technique is developed with MM4 model.A comparison between the adaptive mesh model and uniform mesh model is presented based on the simulation to the heave typhoon rainfall case which occurred in north of China during Aug. 4-5,1996.The results indicate that the simulation accuracy to the synoptic system and its rainfall is better in adaptive mesh model than that in the uniform mesh model.The prediction about the synoptic situation and the wind field has been improved too.