The process of a moviug SW China vortex is simulated in terms of a finemesh model over complicated terrain. It is found that the cumulus convection affects the motion of the SW China vortex. When the cold and warm advection is weak, the powerful cumulus convection causes the south wind in the vicinity of the vortex and the negative vorticity east of the vortex to increase, thus inhibiting the eastward motion of the vortex.