The cooperation of multi-robot that is based on the Multi-Agent System (MAS) theory of distributed artificial intelligence has become a hotspot in the robotics R&D. In the research, the communication and cooperation of multi-agent become the key problem for gaining the dynamic running information of cooperating robots. In this paper we introduce the communication modes for agent and provide a common strategy (which aims at the communication resources of multi-agent model) -the CSMNCD (Carrier Sense Multiple Access with Collision Detection) protocol which is based on the transmittal medium. It supports the cable-communication of multi-robot and the experiments prove its validity.