Abstract: The Sichuan natural gas transmission line is 1414 km long, which provides gas for many industrial and domestic customers of three provinces in the Southwest district. In recent years, pipeline corrosion failures have continuously happened, which resulted huge economic losses and serious environmental problems. The study showed that the SCC (sulfide stress corrosion break) is of the primary contribution to such failures, among which the most important factors are the H₂S concentration, moisture content and pressure. Based on the study, many effective measures have been taken, and resulted a better control of different types of SCC, and the economic and social benefits.