In order to realize the positioning and precise detection of small objects such as electronic chips , twokinds of low distortion optical lens which can be used in machine vision are designed with Zemax software.Thefocal length is 28.5 mm,and the objeet field of view is 10 mm. A traditional refractive lens, with all sphericalsurfaces , consisting of six lenses with a total length of 90 mm is obtained through optimization design. At thespatial frequeney of 100lps/mm, the MTF of all fields of view is higher than 0.5 ,and the maximum distortion is -0.078%. 0n the basis , a refractive diffractive hybrid lens , consisting of four lenses, is further optimized.The total length is 75 mm, MTF is above 0.55 at the same spatial frequency ,and the maximum distortion of 0.071%Considering the influence of diflraetion efficiency of the diffraetive surface on MTF , the aetual MTF of themixed system is still higher than 0.52. Through simulation design, students can not only understand the designcharacteristics of machine vision lens .but also exercise their innovative ability.