Abstract: In this paper, vacillating typhoon tracks in the west Pacific and the South China Sea south of 30°N in Northern Hemisphere are studied based on the principle of dynamics. The results show that in a rotating coordinate system the typhoon circulation rotation affects the vacillating period of the tracks and together with the interaction between the circulation and environmental flow changes the velocity and direction of typhoon movement, with the difference between upper divergence and low-level convergence increasing the track amplitude. Using a predictive equation for the movement, fitting tests are made for various real vacillating tracks and the results are reaso-nably good. In addition, a predictive method for improving to some extent the accuracy of the vacillating track forecast is presented.