Abstract: In order to achieve automatic work of tractor, using a control method combining with feed-forward and feedback control, a nonlinear feedback controller for the automatic lane change of agricultural tractors was designed. First, the nonlinear optimal control algorithm was applied to plan the reference trajectories of automatic lane changes. Then based on the LQ optimal control technique, the feedback controllers for lane change along the planned path were constructed. Finally, the tests were conducted. The results showed that the control method employed in this work had good adaptability, and the designed controller had a good response and convergency.