In order to optimize the transmission performance of 1553B bus and to reduce the transmission delay time of messages on the bus, a scheduling strategy for the mixed periodic and aperiodic messages on the bus was proposed.Firstly, a model for the periodic messages was established according to the scheduling model of periodic tasks, and an improved rate-monotonic scheduling algorithm was presented.Then, the M/M/1 queuing model for aperiodic messages was established based on the queue theory, and the time performance parameters of the 1553B bus were quantitatively analyzed, including average response time, bus utilization, and so on.Furthermore, the delay time for aperiodic messages was optimized.The formulas for optimal bus service rate and minimal average delay time were derived; and the scheduling algorithm of aperiodic messages was presented.Finally, the scheduling characteristic of the mixed messages for above algorithm was validated.The experimental results indicate that the average response time of the mixed messages is only 0.713 ms when the utilization of 1553B bus is up to 96%.The deviation of the average response time between aperiodic messages and M/M/1 queuing model is less than 10% under the condition of transmitting mixed messages.Obtained results show that the algorithm has good response characteristics, and can ensure the real-time scheduling of the periodic and aperiodic messages on the 1553B bus.