Abstract: Gas pipeline leaks due to various factors such as corrosion, natural destruction, human destruction and its own defects etc, in which the vapor cloud explosion will induce the most serious consequences of pipeline failure. In order to assess the material loss, casualties and property damage accurately in the explosion consequence, three kinds of quantitative evaluation methods for the consequences of failure are compared and analyzed to determine their application conditions and the application scopes combined with practical engineering cases. Results show that the assessment procedure in API 581 evaluation model is clear and concise with complete and wide application range, compared with the evaluation model and overpressure-impulse evaluation model in ASME B31.8S-2001, which gives a guide for pipeline risk assessment and integrity management.