Abstract: The welding joints with thickness difference of 20 mm shall be exposed for several times respectively according to different scopes of thickness within the same length of transmission in radiography. We designed and manufactured the shielding panel of lead inclined plane and fixed it on the ray window of ray machine to shield some rays in various degrees. After penetrating the welding joints with different thicknesses, the rays reached the film being basically in accordance with each other. Among the welding joints with thickness difference of 20 mm, the blackness and sensitivity are all in conformity with the standard requirements. When the inspected thickness scope for exposure is increased once, the inspection efficiency can be enhanced twice.