In this paper, the problems of target tracking and obstacle avoidance for multi-agent networks with input constraints are investigated.When there is a moving obstacle, the control objectives are to make the agents track a moving target and to avoid collisions among agcnts.First, without considering the input constraints, a novel distributed controller can be obtained based on the potential function.Second, at each sampling time, the control algorithm is optimized.Furthermore, to solve the problem that agents cannot effectively avoid the obstacles in dynamic environment where the obstacles are moving, a new velocity repulsive potential is designed.One advantage of the designed control algorithm is that each agent only requires local knowledge of its neighboring agents.Finally, simulation results are provided to verify the effectiveness of the proposed approach.