Abstract: The numerical experiments and their diagnostic analyses of the NMC’s typhoon track numerical prediction model, with different parameterization scheme of physical processes were presented. The numerical experiments on Janis (1992) and Herb (1996) typhoons showed that tracks and their landfall locations could be well simulated by this model. Moreover, by using the model with the improved parameterization scheme of physical processes, the thermal regime on high and low level nearby the typhoon center could be better described than that in the original one. Meanwhile, the results from the diagnostic analyses of both the real and simulated typhoon exhibited that the absolute value of first term of MPV1 at 500 or 700 hPa was well related to the intensity of the typhoon. Moreover, the location of the pressure energy and the ascending motion center could indicate the direction of the typhoon’s movement in the next 6~12 hours. Furthermore, results from analyzing 3D thermodynamic structure and the wind field across the typhoon centre showed that the process of strong ascending motion→condensing of warm and moist air→releasing of latent heat→increasing of the temperature→divergence at the high level→dropping of surface pressure→stronger convergence at low level→ascending motion may be a positive feedback mechanisim which caused the typhoon moving forwards to the strong convergence ascending motion area.