This paper is devoted to solve the real-time tracking problem and study the radiation law for transmitting antenna of certain type airborne telemetry system. Firstly, this paper established a simulation radiation model for airborne transmission antenna. Secondly, it analyzed the simulation radiation data for cross-section radiation field intensity of right angle coordinates and vertical-section radiation field intensity of polar coordinates. Finally, it summarized the radiation law for airborne antenna, and the most powerful radiation position was under of air vehicle. The research is useful for optimization of the station layout, tacking strategy, test antenna design and test process plan of telemetry system.