The contribution of diabatic heating to vertical velocity in ω equation for two Meiyu heavyrainfall events occurring 9-10 June 2008 is calculated by us ing the NECP reanalysis data. The feedback mechanism of latent heat release to the Meiyu heavyrainfall systems is interpreted. It is found that the late nt heat release may enhance the ascending motion above the rainfall area and promo te the development of mesoscale systems. The analysis also shows that there are two different kinds of precipitation in the Meiyu front: one is the largescal e continuous precipitation associated with shear line and low vortex; another is the mesoscale heavy rainfall caused by convective heating. Besides that, the dy namic lifting and friction forcing of mountain to the rainfall amplification can not be ignored. 