Abstract: The potential vorticity tendency (PVT) approach can quantitatively estimate the direct contribution of diabatic heating and other physical processes (the non-steering effect) to tropical cyclone (TC) movement. Through the numerical simulation of Typhoon Morakot (2009), the original PVT diagnostic method is improved by including the development of TC asymmetric circulation, and then first uses the approach in the high resolution numerical model results to analyze the impact of different physical processes on the movement of Morakot (2009). The results reveal that although diabatic heating mainly plays a role in maintaining the vertical structure of Morakot, its non-steering effect is important to the short-term oscillations of the movement of Morakot.