This paper further study the real-time problems of CAN bus data transmission. Firstly, through analyzing the main component factors which are message transmission delay, soft delay, hardware delay and medium access control delay of the CAN network delay; optimization measures are further researched to improve the real-time of data transmission. Finally, the validity and efficiency of the optimization measures are tested by experiments. The results show that the average delay respectively reduces about 40%-50%,10%-20%,30%-50% and 10%-30% by improving bus baud rate, using standard frame instead of extended frame, optimizing data field of CAN message, adjusting message transmitting cycle. Although using dynamic priority stepping scheduling strategy has a small increase in the average delay of high priority messages, it also reduces the average delay of low priority messages, which improve the real-time of the whole system.
