Abstract: The safety of marine engineering pipelines is been seriously threatened by environmental corrosion for a long time, and the evaluation of pipeline corrosion damage is of great significance for ensuring the sustainable development of the national economy and society. The principles of tangential radiography inspection and gray radiography inspection in quantitative measurement of corrosion damage was introduced, and the detection errors of the two methods were analyzed. Based on the variation of radial and axial penetrated thickness in the metal path length, a thickness correction method for gray radiography inspection was proposed. The specimen with a flat bottom step hole as a test object, tangential radiography and gray radiography detection were carried out, respectively. The results show that the measured results and the true value of the error was very small, it could be used for pipeline corrosion depth measurement.