Machine vision has been widely used in general, from industrial measurement to managing document, from medical graphic to remote sensing image and from micro technology to multimedia database, too numerous to mention one by one.As it were,where there is human vision,there is almost needs machine vision.Take "Two dimension Photomicrography Precision Measurement System" as a example,it illustrates the basic principle?fundamental structure of machine vision, gives us the present status and development trend of precision measurement in manufacturing, show us the successful application of machine vision for small size precision measurement in manufacturing,and the advantages of machine vision to accurate measurement.