Abstract: The development of urban construction has made underground garages become important supporting facilities, and gas pipelines are also important energy facilities for urban residents to survive. If the two facilities are not properly equipped, they will pose security risks to the operation of the pipelines. Therefore, it is significant to carry out cause analysis of corrosion of the buried gas pipelines in courtyards for future infrastructure planning. The corrosion causes of a 20 steel buried gas pipeline of one district were analyzed by physicochemical property test, corrosion morphology and product analysis of the pipeline. The results show that the corrosive perforation of the pipeline originated from the outer surface and the corrosion mechanism was oxygen corrosion. The structural factors of the flower bed above the pipeline and the underground garage below it, as well as the damage of the external anticorrosive coating of the pipeline were the main reasons for the corrosion perforation of the gas pipeline.