An experimental system for detecting the damage degree of the imaging optical system by using the cat′s eye echo is established, and the peak power of the cat′s eye echo with the irradiation time is summarized. The change mechanism of peak power of cat′s eye echo is analyzed. The relationship between the peak power of the echo and the damage degree of the CCD is established accordingly. Due to the influence of the reflectance and roughness of the CCD in different damage areas, the research shows that the peak power of the cat′s eyes echoes increase dramatically, then decrease significantly with the increase of the damage degree of the CCD. In practical application, it is possible to judge the damage state of the CCD structure according to this rule by detecting the change of the echo strength of the CCD cat's eye.