Abstract: A communication bus system which is based on CAN(controller area network) protocol to fulfill the rigorous demand of AUV(autonomous underwater vehicle) is designed. The protocol switch device which is modularized and configurable make the communication system more exoteric. The fault processing ability and emergencies processing node of the communication system en-hance the reliability and fault tolerance of the system. The system can safeguard the AUV against missing in benthal.