Abstract: Obstacle avoidance for nonholonomic autonomous land vehicle (ALV) is discussed and an obstacle avoidance method based on circle locus is put forward. We induce the constraints of dynamics of four-wheel nonholonomic ALV, which sustain the following work. Obstacles in the road can be layered according to the distances from obstacles to ALV. Thus, one layer of obstacles appears in the view of single camera. We can determine one sub-goal according to the configuration of ALV and the location of obstacles of the layer. The path to the goal of ALV is the iteration of the paths to the sub-goal of each layer. Our algorithm is that the motion to the sub-goal of ALV follows the arc determined by the sub-goal and the initial configuration of ALV. Knowing the start and the sub-goal, we try to reduce the alteration of the running of ALV and the circle locus can best satisfy our need. Finally, applying cost function, our method is evaluated and its advantage is embodied.