A high-altitude military UAV air-to-ground scenario model is established for the battlefield scenario without base station, the MIMO antenna array technology is used to improve the channel communication performance, and the spatial statistical channel model (SSCM) of this scenario is constructed in this paper. According to the simulation results, the dependence of the channel on T-R separation distance, frequency, rain rate and antenna HPBW parameters was investigated, the large-scale fading and small-scale fading characteristics was analyzed. By calculating and analyzing the condition number and rank of the channel transmission matrix, the spatial multiplexing under different MIMO antenna arrays was investigated. The simulation results can provide a theoretical basis for future high-altitude military UAV battlefield situation awareness frequency selection and antenna design.