To address the problem of long time-consuming and large memory consumption of A*algorithm in solving path trajectory,this paper proposes an improved A* algorithm based on adaptive step size.First,the priority order of the search direction was set according to the position relationship between the current point and the end point,with the purpose to reduce the redundant planning calculation on unreasonable directions. Second, the judgment condition for reaching the end point was modified to achieve path jumping during path planning.Then an adaptive step size strategy was proposed to improve the efficiency of A* algorithm in path planning.Finally,an eight-directional search approach was proposed to address the issues of large memory usage and possible memory overflow when facing large maps.Experimental results show that compared with original A* algorithm,the improved A* algorithm greatly improves the efficiency of path planning,and solves the problem of large memory usage.