a clamping apparatus for clamping optical elements includes a first fixture , a second fixture and two mounting members . the first fixture defines a plurality of holding holes . the second fixture defines a plurality of holding grooves corresponding to the holding holes . the holding grooves and holding holes are configured for cooperatively positioning the optical elements . at least one mounting member is configured for adjustably mounting the first fixture and the second fixture so that the first fixture and the second fixture are movable so as to position the optical elements in different positions .