It is essential for robot to have the sensing and communication abilities in the swarm robot system. In general, as the number of robot goes on increasing, the limitation of communication capacity and information overflow occur in global communication system. Therefore a local communication is more effective than global one. In this paper, we analyze information propagation mechanism based on local communication. To find an optimal communication radius, we propose several methods with different conditions. Also, to avoid chaotic behavior which occurs when a robot obtains and loses information, we will suggest the stable condition of information propagation.