Abstract: A digital fish-eye lens for dome-screen projector applied to 0.63 inch 3-liquid crystal on silicon(3LCD) projectors was designed in Zemax based on the principle of non-similarity. The lens is composed of 6 spherical lenses, and has the retrofocus optical structure. Its image quality is excellent with the advantages of simple structure, low cost and easy process. The full field of view (FOV) of the lens is 180, the effective focal length (EFL) is 3.28 mm, the relative aperture is 1/1.9,the back focus length( BFL) is 35.8 mm and the length of optical system is 196 mm. Its modulation transfer function (MTF) in all field is higher than 0.4 at 50 lp/mm. The lateral color is less than 4.5 m. The absolute value of F-Theta distortion of the full of view is less than 3%. The relative illumination of the image in the maximum of view is 96.27%.