Abstract: To fully utilize the historical failure data of oil and gas pipelines and minimize the subjectivity in evaluation of failure probability, the concept and evaluation method of basic failure probability of oil and gas pipelines were proposed.The mileage, accident and failure factor data of oil and gas pipelines in the Pipeline and Hazardous Materials Safety Administration(PHMSA) database in the United States were comprehensively analyzed, and the basic failure probability of oil and gas pipelines was evaluated based on accident statistics.The results show that the basic failure probabilities of ordinary accidents of hazardous liquid pipelines, gas gathering and transportation pipelines and gas distribution pipelines in the United States are 1.29 times/(10³ km·a), 2.17 times/(10⁴ km·a) and 4.08 times/(10⁵ km·a), respectively, Those of larger accidents are 4.58 times/(10³ km·a), 1.41 times/(10³ km·a) and 2.38 times/(10³ km·a), respectively, and those of serious accidents are 9.09 times/(10⁶ km·a), 9.79 times/(10⁶ km·a) and 1.11 times/(10⁵ km·a), respectively.American basic failure probabilities could be used as the baseline for evaluating the failure probability of oil and gas pipelines or as the basis for risk acceptance criteria.However, they can't be directly applied to the pipeline risk assessment in China and should be amended to establish failure database for chinese pipelines.