In order to solve the shortcomings of the original RRT in the field of path planning, such as long planning time, uneven path and high path cost, this paper first added dynamic step strategy and embedded Dijkstra algorithm on the basis of the original RRT algorithm to improve efficiency. Then, lower sample smoothing, upper sample smoothing and key point smoothing are added to the obtained path to improve the path smoothness and path cost. MATLAB experiments show that the proposed algorithm improves the planning time by about 45% compared with the traditional RRT algorithm, and is 30% to 70% ahead of Astar, RRTstar and GA algorithms respectively. In terms of path length, the proposed algorithm has a nearly 40% improvement over the traditional RRT, and it also has different degrees of lead compared with other algorithms. It can be concluded that the method proposed in this paper can be well applied to path planning.