Proportional-derivative(PD)control with a dead band algorithm is suc- cessfully used for the model tractor wheel-slip system.The tractor wheel-slip is maintained around the predetermined value through adjusting the tillage resistance. This will reduce the tractor energy loss and prevent the tractor wheel empty run- ning without forward speed on wet ground.The performance of PD control is illus- trated by the indoor test on an indoor soil bin.