Abstract: Inspection staffs that do not enter the furnace interior can easily operate the equipment to radiograph the cross weld of the screen platen spacing tube at 800 mm below the ceiling with the simple mechanical hand “mobile gamma hole”. The inspection is realized as follows: the film is fixed on the pitch roof tube 800 mm below the ceiling over spaced pipe welding seam area through the tube frame with “mobile gamma hole”, clamp, and magnetic clip;the positioning is based on beforehand calculation. Through theoretical data, special gamma source bending center collimator with “mobile gamma hole”, clamp, and magnetic clip on gamma ray exposure head were used for precise positioning. Then according to the conventional method of operation processing, the films meeting the standard were obtained. As compared with the traditional method this new method is characteristic of safety, economy and environmental protection.