A new local path planning algorithm for free-ranging mobile robots is proposed. considering that a laser range finder has the excellent resolution with respect to angular and distane measurements, a simple local path planning algorithm is achieved by a directional weighting method for obtaining a heading direction of mobile robot. The directional weighting method decides the heading direction of the mobile robot by estimating the attractive resultant force which is obtained by direcctional weghting function times range data, and testing whether the collision-free path and the open pathway conditions are satisfied. Also, the effectiveness of the established local path planning algorithm is estimates by computer simulation in complex environment.