Aiming at the characteristic that the heavy-load harvesters would easily slip and sideslip and its nonlinear large-lag control system, a method of compensating the sideslip and relieving the hysteresis in path tracking for heavy-load harvesters was proposed in this paper. After establishing a kinematic model, the equivalent sideslipping angle was estimated according to the previous and the present state of the harvester, to compensate for the expected wheel steering angle. The featured state of the harvester can be predicted according to the present state and speed of the harvester to adjust the present lateral error and heading angle error to optimize the expected wheel steering angle calculated by the path tracking algorithm, which can improve the accuracy and stability when the heavy-load harvester is working. The validity of the proposed algorithm was verified by experiments at the speeds of 0.6 m/s and 1.0 m/s, respectively. The maximum lateral errors of the harvester were 8.3 cm and 13.9 cm, respectively, and the standard deviations were 3.01 cm and 4.09 cm respectively. The results show that the strategy proposed in this paper can effectively reduce the lateral error and achieve accurate path tracking control.