To solve the problems of the traditional A* algorithm and the traditional dynamic window approach （DWA） in mobile robot path planning， a dynamic path planning method combining the improved A* algorithm and the improved DWA is proposed. First， the 16-neighborhood and 16-direction path search method is adopted to expand the path search field and reduce the number of the nodes accessed and the turning angles. Second， the heuristic function is optimized to enhance the purpose of the path search. Next， the redundant point deletion strategy is adopted to reduce the number of the turning points and further improve the smoothness of the path. Third， the path corner is processed by the B-spline curve， and the path is relatively smooth. Then， the sensitivity of obstacle avoidance can be improved by classifying and treating obstacles differently and adding the speed adaptive factor in the evaluation function of DWA. Finally， through three parts of the simulation experiments with the other algorithms， and the priority strategy simulation experiments， the effectiveness of the improved A* algorithm and the superiority of the fusion method in obstacle avoidance are verified.