APF-A* algorithm is proposed to solve the problem of how to reduce the invalid repeated path segments caused by complex terrain in unknown environment. The nearest-neighbor boundary point selection strategy is used to ensure the high coverage rate of the planned path in the unknown environment, and the artificial potential field algorithm is used to improve the evaluation function of the traditional A * algorithm. The algorithm is tested on a grid map. The results show that the path planned by APF-A* algorithm reduces the total path length by more than 5.3% and the average path repetition rate by more than 5.4% compared with the A* algorithm. This proves that the APF-A* algorithm can effectively reduce invalid duplicate path segments.