Regarding the problem of the Informed-RRT* algorithm of collision with dynamic obstacles in path planning, an improved path planning algorithm based on Informed-RRT* and artificial potential field method is proposed.The algorithm introduces elliptical region sampling strategy and adaptive step-size strategy to improve the stability and efficiency of finding feasible global path, and the optimal cost feasible path scheme is obtained in the boundary region of static obstacles.When the robot encounters dynamic obstacles in its movement according to the global path, the cutting path branching strategy and artificial potential field method are introduced to re-plan the local path to realize dynamic obstacle avoidance.The improved algorithm is applied to the simulation environment, and the results show that the improved algorithm achieves the functions of global optimal search and local obstacle avoidance, which verifies the effectiveness of the algorithm.