Abstract: On the basis of analysis of principle and application of CAN protocol，the paper designed a new CAN bus application layer protocol according to specific working requirements of logger. The application layer protocol was used to underground logger. On the basis of agreement CAN2.0, the protocol refers CANopen protocol specification to redefine the identifier and construct a new type of CAN bus network mechanism accommodated multi-node, so as to realize networked synchronous communication between nodes of monitoring tube and upper computer.