Abstract: On the basis of applying the two radiographic testing standards i.e. JB/T 4730.2—2005 and DL/T 821—2002 to the inspection of power boiler, effect on their directing practice has been analyzed and an improvement on controlling quality of JB/T 4730.2—2005 has been clarified by comparing of relevant definitions and important technical steps of radiographic testing skill and quality grading of small diameter tubes, in order to give a reference to inspection agency and inspector for correct performing the above standards.