Aiming at the QoS(quality of service) and delay problems of aeronautic Ad Hoc network under high load, a DQM transmission mechanism was proposed(dynamic QoS of multi-channel MAC). On the basis of multi-channel detection statistics and the priority mechanism, the DQM optimized the network traffic via shutting down the low-priority traffic in the high-load network timely to ensure the low-latency transmission of high-priority traffic. The traffic prediction model was used to estimate the network traffic. Combined the particle swarm optimization algorithm, the DQM could find the optimal priority threshold and guarantee the access rate of highpriority services. Simulation results prove that the DQM maintains an optimized network traffic by adaptively controlling channel access in high-load network. Thus, the access rate of high-priority services reaches above 99%, which helps to solve the QoS and latency issues associated with high traffic in the air data link.