To realize the miniaturization and light weight of the digital projector, a wide-field angle mini lens for 0.55 inch DLP was designed. The total length is 69 mm, the full aperture is 25 mm, and it is composed of five glass lenses and two plastic lenses(4 aspheric surfaces).The lens used an inverted telephoto structure, with ZEMAX software as the optimize tool. Its F-number is F/2.4, the projection ratio is 0.73∶1, and it can project a 40 inch picture from 60 cm away. The distortion of the full field is less than 1%. Its image quality is excellent that the MTF of center field is 0.75, and the MTF of 1.0 field is 0.42，with advantages of small size, light weight, low cost, simple structure and easy process.