For the large aperture reflecting mirror with flexible strip support, static friction between large aperture optical reflecting mirror and support stripe has great influence on surface distortion of reflecting mirror. Moreover, the influence is hard to measure in quantity directly. In consideration of the fact that ambient temperature fluctuation would lead to state change of static friction, relational expression of temperature-static friction was established. On the basis of the relational expression, the influence of static friction on reflecting mirror surface distortion could be deduced though measuring reflecting mirror surface distortion at different temperatures. By taking a 1.2 m SiC light-weight reflecting mirror with flexible strip support mechanism as research object, the surface distortion measurement of flexible strip support mechanism was conducted at different temperatures with a interferometer, and corresponding coefficients of temperature-static friction relation were calculated with measured data; simulation analysis on force condition of stripe support mechanism was conducted with ANSYS software. The results indicate that measured result and simulation analysis result have good consistency, thus influence of static friction on mirror distortion of large-aperture SiC light-weight reflecting mirror can be deducted accurately in this proposed method.