In the vacuum environment,the pressure regulator outlet pressure of the turboprop aircraft engine anti-icing system decays and the switch position signal cannot be fed back.The vacuum bellows structure was used to improve the pilot valve structure of the pressure regulator to ensure the stability of the pilot chamber pressure.The AMESim software was used to simulate the performance of the pressure regulator.The minimum opening angle of the butterfly plate was calculated under normal working pressure,so as to adjust the micro switch and realize the position signal indication in all working areas.The test results show that:in vacuum environment,the outlet pressure fluctuation of vacuum bellows structure pressure regulator is small relative to the ground environment,which can meet the requirements;the calculation results of the butterfly plate opening angle are more reliable through the AMESim software,which provides a strong support for the setting of the switch status signal.