Abstract: By numerical study and diagnostic analysis for Typhoon 9216,it is found that the process of the typhoon rainstorm is associated with the development and propagation of meso－α-scale intertial gravity wave(IGW),the distribution of heterogeno us stratification and the latent heat feedback of cumulus convection.The nonlinear advection for large scale excites the large scale IGW.The heating of cumulus convection latent heat feedback is responsible for the strengthening the ageostrophic wind,whose effect gives rise to the development of IGW amplitude,ascending motion and rainstorm.When IGW propagates along the direction in which the degree of stability is decreased,the IGW energy is reinforced easily.