Abstract: TTCAN(time-triggered CAN) is a protocol based on CAN bus and it considers the advantages of time-triggered mechanism. Since messages are diverse, it is hard to schedule real-time tasks which constitute TTCAN systematic matrix. So, a greatest common divisor (GCD) method is proposed to solve the problem, where genetic algorithm (GA) is used to optimize the scheduling table to improve the network utilization and timeliness in event-triggered tasks. Finally, fault-tolerant performance is analyzed and a method of behind-priority principle for arbitration windows is proposed. Experimental results indicate that the algorithm can optimize the scheduling table, thereby ensuring real-time transfer.