Cross bar of mouldboard plough of Massey Ferguson 399 Tractor was investigated by finite element method in point of failure analysis. A 3-d model of the cross bar was provided in ANSYS Software, and the constraints, boundary conditions, and loads were applied on the model. The fatigue analysis was done on the model after static analysis. The exerted loads were calculated based on the maximum draft force of the tractor. Based on Soderberg criteria, the safety factor in fatigue analysis was calculated and that of the left hole of the cross bar was minimum as 1.82 that shows higher failure probability of that. The result of fatigue analysis in the present research is in agreement with that practically is happened for mouldboard plough cross bar.
