The antenna equipment in high altitude environment is very easy to be affected by corona discharge, in order to improve the insulating performance of the equipment, this paper establishes a rod-plate gap model to simulate the corona discharge of inhomogeneous electric field in high altitude environment, and the air pressure and temperature are used as the characterization parameters of the high-altitude environment. It is shown that the corona discharge gradually accelerates with the decrease of air pressure, the maximum value of the electric field strength gradually decreases, while the electron concentration, N2+ concentration gradually increase with the decrease of air pressure. When the temperature decreases, the corona discharge slows down, the maximum values of electric field strength and electron concentration increase. And the peak of N2+ concentration decreases with the decrease of temperature.