Abstract: Obstacles avoidance for four-wheel nonholonomic autonomous land vehicle (ALV) was discussed, and an obstacle avoidance method based on circle locus was put forward. The principle of obtaining the information of depth by parallel moving lens was given. The dynamic models of four-wheel nonholonomic ALV were lucubrated. The constraints of dynamics and obstacle avoidance were induced. Obstacles in the road can be layered according to the distances from obstacles to ALV. Thus, one layer of obstacles appear in the vision view of single camera. One sub-goal can be determined according to the configuration of ALV and the locations of obstacles of the layer. The path to the goal of ALV is the iteration of the path to the sub-goal of each layer. ALV follows the arc determined by the initial configuration of ALV and the sub-goal. Knowing the start and the sub-goal reduces the alteration of the running of ALV.