The utility model discloses a trans measurement optical system is rolled over to big visual field includes first lens, second lens, third lens, fourth lens and the 5th lens from the object plane to image planes. First lens and second lens set up along formation of image optical axis parallel, and the rear of second lens sets up the plane holophote of a slope 45, make the formation of image optical axis deflect 90, and third lens to the 5th lens the formation of image optical axis parallel along deflect after set up, set up a diaphragm between third lens and the fourth lens, first lens are the glass lens and the object plane is convex spherical for little convex spherical, image planes, the second lens are the glass lens and the object plane is convex spherical, image planes is the concave spherical surface, the third lens are the veneer lens, the fourth lens are the veneer lens, the 5th lens are the glass lens and the object plane is the plane, and image planes are convex spherical. The utility model discloses a measure optical system, reduced the restriction that just can not receive into the image space 23 or more with whole imaging lens's optical length.