The cat′s eye echoes model of the optical imaging system under different damage conditions was established and the influence of the damage to the charge coupled device layers on the cat′s eye echo power was analyzed. Based on this, the corresponding relationship between the echo power of the cat's eye and the damage degree of the CCD was established and verified by experiments. The results show that the field intensity is the strongest in the center of cat′s eye echo which is from imaging optics system, and the power of the echo increases dramatically and then decrease steeply and decrease slowly with the damage degree more serious. The damaged status of CCD can be judged according to this rule. The study results have certain reference value for monitoring the damage degree of CCD in real time in the far field.