Abstract: A fan-shaped grid map based wave propagation algorithm(WPA) for global path planning of mobile robot in a known environment is described.In the approach,a fan-shaped grid map based on the polar coordinate is used to describe the environment of mobile robot and a grid-connected six-tree model is established.Then,the grids are valued and the approximate paths are searched through the implementation of the grid class.Lastly,the final planned path is obtained through the evaluation and optimization of approximate paths.The concepts of circle-road and circle-area are introduced in this approach,the radius problem of WPA is solved and its complexity is O(n).Simulation and experiment results illustrate that the approach is practical and time-saving.