Abstract: A modified and improved primitive equation model with p-sigma incorporated vertical coordinates is used to simulate the climate properties in the summer monsoon area.The model includes various diabatic physical processes and the effects of the large scale topography and 6 kinds of underlying surfaces.Detailed discussions are made on the simulated mean fields of pressure, flow, precipitation and evaporation, soil temperature and moisture, and the diabatic heating fields.The results show that the simulated mean climate properties in the summer monsoon area are quite similar to the observed ones.The model simulated the surface climate, too, and shows that the surface climate characteristics are closely related to the atmospheric states and the physical properties of the underlying surfaces.The simulated heating fields show that the heating due to the cumulus convective condensation has the most important contribution to the total heating field.