This paper presents a new obstacle avoidance control method for multi-mobile robots formation in complex environment. At first, the formation based on the methods of leader-follower and artificial potential is built for multi-mobile robots; And then, the leader robot avoids obstacles autonomously, the follower robots track the leader robot, and detect obstacles by the sensors and then avoid obstacles; At last, the robots formation arrived their goal after avoiding obstacles and resuming their formation. The simulation results proved that the presented method is valid.