In the study of fourwheel drive vehicle traction control system, there is a deviation regarding the tire longitudinal force from Gim tire model as ground driving force directly. A correction method for ground driving force was proposed, and simulations on both high and low adhesion coefficient ground were carried out to simulate the influence on the vehicle velocity with the deviation of ground driving force. The simulation results show that the deviation of ground driving force is almost zero on the high adhesion coefficient road. But on the low adhesion coefficient road, the deviation of ground driving force has a significant influence on vehicle velocity. There is a larger deviation of ground driving force on the low adhesion coefficient road, which significantly affects the control precision of the fourwheel drive vehicle traction control system. The proposed correction method for ground driving force improves the accuracy of the traction control system.