Tropical cyclone motion is numerically simulated in the context of a quasi-geostrophic three-layer baroclinic model with detailed analysis of an asymmetric circulation and its relation to the cvclone motion,Restilts show that combination of the linear beta term and nonlinear vorticity advection produces gyres both of large and small scales and that the steady interaction between these pairs will lead to the oscillation in speed and vacillation in direction for a tropical cyclone.