Abstract: In the application of digital radiography (DR) testing for girth weld in long-distance pipelines, the detection and evaluation of welding quality not only depends on the hardware of the detection system (such as X-ray sources, digital imaging versions, etc.), but also on the practical operation and evaluation experience of quality inspectors. Especially in the process of evaluating defects, the post-processing software function of digital images is very important. This paper was based on the industry standard requirements for digital radiography testing of girth weld in long-distance pipelines. In response to the characteristics of girth weld detection images, specific image processing system were developed, and detailed solutions for each functional module were provided. Practical applications showed that the software had strong targeting and applicability, and could provide a convenient and fast human-machine interaction platform for the evaluation of digital radiography testing of girth welds in long-distance pipelines.