Aims at the formation and obstacle avoidance problems of multi-robots in unknown environments, and designs a formation and obstacle avoidance control algorithm based on following the pilot, so that the multi-robots can maintain a certain formation without collision, and can make the local obstacle of robot in unknown environment also can safely avoid obstacles, after over obstacles still can resume before the formation of formation. A multi-robots system is designed and simulated, and the experimental results show that the proposed method has good effect on the formation and obstacle avoidance control of multi-robots.