Abstract: During the maintenance of the pipeline network of oilfield gas well clusters, it was found that there often occurred corrosion pits in some weld roots and the inner wall of the base metal had corrosion pits. The main shapes were pitting corrosion and flaky corrosion, which constituted a great hidden danger to the safe operation of the pipeline. Therefore, it is necessary to prevent corrosion. In-depth accurate measurement is used as the basis for RBI (Risk Assessment-Based Equipment Inspection) analysis. Traditional ultrasonic testing, phased array testing, and eddy current testing are often difficult to determine the maximum corrosion depth of the small area corrosion pits on the inner wall, and the measurement reliability of the corrosion pits in the weld and its adjacent areas is low. With the help of digital radiography detection technology (DR), the corrosion depth-image gray scale mathematical model was established through experiments, and the accurate measurement of corrosion pit depth was realized.