During the heating process of hot air anti-icing cavity, the temperature difference between the inner and outer skin is large, which will result in the changes of the gap between the two skins due to the thermal expansion deformation andinfluence anti-icing effect, even block anti-icing passageway. This paper is focused on the hot air anti-icing system of a certainengine inlet aspect. In order to solve the thermal deformation of double skin anti-icing cavity, the method of adding the numberof shims between the two skins is chosen. The finite element method was used to analyze anti-icing cavity’s thermal deformation,and obtained the maximum thermal deformation area and the change law of thermal deformation the anti-icing cavity of under different number of shims conditions, which provides the design foundation of the double skin anti-icing cavity.