Abstract: The potentiometer of electric plastic film is widely used to measure the absolute angle in space, but less so in China, where the irradiation testing and the related research of the potentiometer are very few. But this kind of studies is important if the potentiometer could be applied in a long-life space assembly. This paper presents the method and the principle of the potentiometer irradiation test. The performances of the potentiometer before and after the irradiation are compared. The experimental results show that the performance of the potentiometer can meet the requirements. The research provides a valuable reference for the further application of the potentiometer in spaceborne long-life mechanisms.