Aiming at the problems that traditional DWA algorithm is easy to fall into local optimum and dynamic obstacle avoidance is poor in complex dynamic environment, an improved DWA algorithm based on A* was proposed. Firstly, a collision cone is introduced into the DWA algorithm to detect the static and moving obstacles, and the speed with collision threat is eliminated through the speed window to optimize the constraint space. Secondly, the evaluation function is improved according to the static and moving obstacle information to improve the trajectory evaluation ability of DWA algorithm. Finally, the improved DWA algorithm is integrated with A* algorithm to solve the problem that DWA algorithm is easy to fall into local optimum in complex environment. Simulation results show that compared with other similar algorithms, the proposed algorithm can improve the traveling speed and safe distance by more than 50%, which not only can make the robot travel according to the global optimal path, but also effectively improve the robot′s obstacle avoidance ability in complex dynamic environment.