To make the lens small in size, compact in structure, and to make the illumination at its image plane even as well, the front lens is designed with“negative positive”telecentric structure in the image space and aspheric surface. The result of design is shown with calculation and op timization of op tical design software ZEMAX, whose operating wavelength, focal length , angle of view , relative aperture , optical length respectively are 0. 8～1. 1μm, 5mm,60°, 1∶3. 8, 47. 5mm. TheMTF value of the lens is 0. 78 at the spatial frequency of 31 lp /mm.