This paper is focused on the fully distributed cooperative motion of group robots and proposes a new approach. Each robot has a local sensing ability and a simple action selection strategy. Computational complexity is decreased by the fully distributed architecture and the information insufficiency is solved by the interaction between the robots and the environment. Variable loop and random method are used to deal with the fluctuation and equity selection problem and the rapidity and reasonabiliiy are guaranteed. Some simulations have proved the effectiveness of the proposed approach.