Abstract: In order to solve the priority problem of tactical data link，a prioritized two-level polling control strategy based on exhaustive access strategy and asymmetric gated access strategy is proposed for media access control in tactical data link.In the polling control strategy，an asymmetric gated access strategy is adopted for the low priority outposts in tactical data link，and the exhaustive access strategy is adopted for the high priority outposts.When the network control site is transferred from the high priority outpost to the low priority outpost，the transmission service and the transfer query are processed in parallel to reduce the time cost during the query conversion，and the operating efficiency of the polling system is improved. The Markov chain and probabilistic generating function are used to establish the mathematical model of the polling system，which accurately resolves the expression of the average number of information packets waiting to be sent in each outpost. The approximate expression of the average waiting time for the information packets in the outpost is resolved by using the second-order characteristic quantity approximation method of the cyclic period. The simulated results of the proposed model show that the experimental value is approximately equal to the theoretical value，and the service quality of the high-priority outpost is better than those of other outposts，indicating that the theoretical analysis is correct，and the proposed model achieves the purpose of prioritizing. Key

Key words: tacticaldatalink, mediaaccesscontrol, pollingsystem, priorityoutpost, averagequeuelength, averagewaitingtime