Abstract: The optics window of photoelectric equipment has strong reflecting characteristics for the incident laser beam, which is known as cat eye effect. In order to study the suitability of cat eye effect for active laser detection and analyse the effect of the incidence angle on reflected characteristics of cat eye effect, a perfect reflecting model of cat eye effect in the gradient circs was founded, then analysis and simulation of the back-reflected laser characteristics of cat eye effect were done with various incidence angle of the detecting laser at the target optical system. Moreover, the far field energy distribute characteristics of the return laser beam which could be received by the detecting system were gotten. The results show that cat eye effect only exist when the incidence angle o