Abstract: In order to meet the requirement of the miniaturization and light weight for field projector both at home and abroad,we designed a short focal digital projection lens for the 1.19 cm (0.47 inch),1080 pixel digital micromirror device (DMD) chip from TI.It is composed of 7 glass lenses (all common glass) and 2 plastic lenses (4 aspheric surface) with simple structure,and is easy to process.The projection ratio is 0.66:1 and it can project a 111.76 cm (44 inch) picture at the distance of 600 mm. The effect focal lenth is 6.4 mm,the Fnumber is:F/2.1,the full field of view(FOV) is 86,the total length is 46mm,the full aperture is 22 mm,the modulation transfer function (MTF) is more than 0.62 at the spatial frequency of 93 lp/mm within 0.8 FOV, the MTF of 1 field is 0.43,the distorition of the full FOV is less than 2%, and the vertical chromatic aberration is less than 0.18 m.