Abstract: To test the typical butt weld of the small diameter pipes on the auxiliary pipelines in the nuclear power plant, reference samples were designed and manufactured according to the regulations and requirements specified by Level 1 of RCC-M of the radiographic testing and acceptance. Systems constructed by the same radiation source but with film and the digital radiography images, respectively, were used to test the above-mentioned samples and testing results including their respective imaging quality and the flaw detection ability were analyzed and compared. The results show that it is feasible for the digital radiography to test the small-diameter pipe in the nuclear power industry.