For improving real-time accurate strike capability and the low delay transmission in high traffic-load of new data link in the modern battlefield, the MAC layer adopts an improved algorithm named Priority Statistic based on Multichannel Access Method（PSMC ）with Ad Hoc network as a basis. In the protocol the mode of comparing the priority threshold value with the channel occupancy statistics is adopted to determine whether to transmit the data or not. Also mini-slot and cell are adopted to protect data transmission reliability. Simulation results show that PSMC protocol can ensure that successful sending of data be maintained at the level of very low delay and satisfy the QoS of every Priority, especially provide real-time, safe guarantee for the high-priority. Compared to classic protocol of ALOHA, Slotted ALOHA, the results show that PSMC can carry heavy traffic load and ensure high throughput. Even in the case of overloading, it also can go on working with throttling back traffic.