A path planning method for UAVs is presented. First, through mission scenario, a Voronoi diagram is constructed, based on this, space decomposition network model and Resenthal algorithm are used to compute the coarse path - a series of straight-line segments and not flyable. Then, using a series of cubic splines to connect these straight - line segments, the path is refined into an optimal one that is flyable for the UAVs. Simulation result shows that this method is simple, effective and of a certain value in application.