Considering the cat-eye effect based retro-modulating laser communication as the application background, a large-field cat-eye echo power distribution model is established based on the Collins diffraction formula by transforming the angular misalignment of the cat-eye lens into a line offset. The effects of the defocusing amount, incident angle, cat-eye diameter, and focal length on the echo power distribution and original return characteristics of the cat-eye echo beam are analyzed and verified with experiments. The results show that the larger the incident angle is,the smaller the echo spot area is,and the stronger the diffraction is. At the same incident angle, the larger the aperture of the cat-eye is, the smaller the focal length is, and the smaller the echo spot affected by the incident angle is. The divergence angle of the positive defocus echo spot at the same defocusing amount is smaller than that of the negative defocus. The center shift of the cat-eye echo varies linearly with both the incident angle and the defocusing amount, and there is a positive defocusing amount that causes the echo beam to return to the original path.