Abstract: The detection ability of a non-destructive testing method shall be obtained by comparing NDT data and imperfection true parameter derived from destructive tests. By a combination of DNVGL standard and application in subsea pipeline project, destructive tests and key techniques are researched in this article which contains positioning and marking on test piece of imperfection, machining process, slice disposal, imperfection measurement, etc., and this developed procedure has practical and instructional significance of destructive test in NDT method qualification in subsea pipeline project.