Abstract: Aiming at the problem that traditional film radiographic inspection technology is difficult to perform full volume inspection of high pound nuclear power valve body with complex structures and large wall thickness,this paper taking a typical product with diameter is 6 inch(1 inch=25. 4 mm) and the bearing mass is 1500 lb (1 lb=0. 45 kg) check valve as an example, The detection process is optimized from the division and identification of detection area, the application of double films technology, thickness compensation block technology and pre-exposure technology to achieve the purpose of full volume inspection as required by the specification, which can provide a reference for peers.