The CAN bus communication system of vehicle-mounted rig was studied in order to implement data transmission reliably between all nodes in the communication system of the vehicle-mounted dig. The hardware structure of the communication system was designed, and CAN network was built with CANopen protocol, SAE J1939 and CAN2.0B protocol applied in each network respectively. All CAN protocols that used and software were designed in detail. It was known that the CAN messages sent and received were correct by analyzing the result of information of CAN messages based on CAN2.0B and J1939 protocols. The application results of the actual engineering show the reliability of data transmission between each CAN interface and the application of active significance for vehicle-mounted drill rig.