Abstract: In view of problems of bad real-time performance and uncertainty caused by big delay of low priority data existed in underground CAN communication network, the paper proposed a TTCAN protocol based on time-triggered mechanism. It gave hardware structure of TTCAN network system composed of master node and slave nodes, introduced design of TTCAN dispatching algorithm based on Level 1 synchronization mode. The experiment result shows that the biggest respond time and the biggest sending cycle jitter of TTCAN network are almost not influenced by increasing of information and reducing of priority comparing with standard CAN network, so TTCAN has better real-time performance and certainty.