Sideslip phenomenon often occur when land leveler works in farmland environment, in order to reduce the influence of sideslip angle on path tracking accuracy, an adaptive guidance control method with sideslip estimation for land leveler pulling by tractor was proposed. According to the position relationship between forklift and tractor, the kinematic model of land leveler was established. A sideslip estimator based on the kinematic model was designed, which could predict the wheel slip angle due to sideslip during navigation control. Moreover, the front wheel angle control rate considering sideslip effect of tractor was calculated. Finally, an improved nonlinear function construction method was adopted to adjust the parameters of PID controller KP, KI and KD in real time to realize the adaptive control of the farmland leveler. The results of fields test showed that the path tracking mean absolute lateral of the leveling shovel in this method was reduced by 6.78cm, and the standard lateral of the leveling shovel in this method was reduced by 10.1cm. Compared with the navigation control method with no sideslip estimation and parameters adaptive, this method can improve the path tracking accuracy and the adaptability and robustness of the navigation control system for the farmland leveler.