Abstract: Based on the theory of angular spectrum diffraction, the diffraction transmission of the cat-eye effect reflected light under oblique incidence is derived by two-dimensional discrete Fourier transform and projection combination of the two diffraction apertures. Through numerical computation, the variation laws of the diffraction field distribution with the incidence angle and diffraction distance are given. Then an experiment is conducted to validate the law affected by the incidence angle. The results show that the method used in this paper can exactly describe the diffraction field distribution of the cat-eye reflected light under large angle oblique incidence, and the effect of incidence angle increase on the diffraction mode of the light field can be equivalent to the effect of diffrac