The invention relates to an automatic inflation device for an aircraft tire. The automatic inflation device comprises a main pipeline, a controller and an electric source connected with the controller, wherein an air source connector is arranged at one end of the main pipeline and an inflation connector is arranged at the other end of the main pipeline; and an air source pressure gauge, a pressure reducer, an inflation pressure regulating valve, an inflation solenoid valve, a pressure-measuring pressure gauge, a pressure transmitter and a deflation solenoid valve are arranged sequentially on the main pipeline in the direction from the end with the air source connector, of the main pipeline, to the end with the inflation connector, of the main pipeline, and the inflation pressure regulating valve, the inflation solenoid valve, the pressure transmitter and the deflation solenoid valve are electrically connected with the controller. The automatic inflation device of an aircraft tire provided by the invention is simple in structure and convenient in operation; repeated inflation and deflation as well as pressure testing are not needed; inflation can be automatically completed simply by connecting the pipeline; the pressure displayed by the pressure-measuring pressure gauge is the current tire pressure; and inflation is accurate and safe.