The research on the comfort of tractor seat plays an important role in reducing the occurrence of driving safety accidents and improving the health level of drivers. In this paper, the human body model is added to the Pro/E Manikin module, and the human model is chosen as the P50 male and female human model. The tractor cab is modeled by using Pro/E software. The four parameters range were adjusted cushion angle, length between heel points to steering wheel, height from heel points to steering wheel, the steering wheel angle, then get the value of the RULA analysis.