Abstract: On the basis of the WDM broadcasting network structure, a real time scheduling method for avionics periodic or aperiodic real time messages named MMAS (multichannel multiclass avionics scheduling) was proposed to improve the utilization of the channels. For the periodic real time messages, the multichannel static round robin scheduling method was applied, in which the RL parameter optimization strategy was involved to increase the load rate of channels and decrease the fragments of the bandwidth at the same time. The message allocation method was provided to reduce the splitting times of the messages. For the aperiodic real time messages, the dynamic reservation multichannel scheduling method was adopted. The surplus bandwidths of periodic messages in every period were reused to improve the utilization of the channels. Then the admitting control condition for aperiodic messages was presented. The evaluation of an example verifies that the utilization of the channels could be efficiently increased by using the RL parameter optimization strategy, channel allocation method and the surplus bandwidths reused method. Also the splitting times could be lowered by allocation method for periodic messages.