In order to solve the problems of slow on-line speed, low accuracy and poor anti-interference ability of unmanned paddy field plant protection machine in field operation, a kind of paddy field plant protection machine path tracking control based on fast power reaching law and global sliding mode control was proposed. Firstly, a kinematics model of four-wheel out-of-phase steering of a paddy field plant protection aircraft containing slip interference terms and heading angle interference terms was established, and the four-wheel out-of-phase steering model was simplified to a two-wheel out-of-phase steering model. A linear operation tracking steering control algorithm based on global sliding mode control and fast power approaching law was proposed, which solved the problem that the buffeting and approaching modes of sliding mode control algorithm were sensitive to interference. The Lyapunov criterion was used to test the convergence of the algorithm. A simulation model was established by using Matlab and the algorithm was simulated. Compared with the sliding mode control algorithm based on exponential reaching law and constant velocity reaching law, the speed of the algorithm was better. The actual operation experiment results showed that the maximum absolute value of the lateral deviation of the linear tracking of this method was 0.0778m. Compared with the sliding mode control algorithm based on the constant velocity approaching law, the proposed method was effective in overcoming chattering and anti-interference, and can effectively improve the stability and speed of the autonomous navigation control system.