In this paper, the thermal properties of a super-thin multilayer metal mirror with silicon substrate subjected to irradiation of high power lasers are experimentally demonstrated and theoretically analyzed. The structural designs for the mirror and the relations between thermal deformation and laser irradiating time are presented. The results show that under the condition that absorption laser power is 120 W, and laser irradiating time 4 s, the thermal deformation of the silicon super-thin multilayer mirror is 0.25 μm, but that of the general silicon mirror 0.71 μm. Theoretical calculations are relatively accordant with the experimental results.