Abstract: To prevent the casualties and property losses caused by urban gas pipeline leakage, the scenario evolution paths of urban gas pipeline accidentswere studied using the scenario construction and deduction theory, and the influence range of the accidents was explored. With the "7.4" gas pipeline leakage and explosion accident in Songyuan, Jilin as an example, a dynamic Bayesian network model of urban gas pipeline accident was established based on the situational state, emergency target, emergency disposal measures, external environmental impact and other factors. In this way, the scenario network was constructed, the scenario probability was calculated, and the accident evolution law was analyzed. In addition, simulation analysis was performed with FLACS software for the scenario of urban gas pipeline accident based on scenario construction and deduction.The results show that: the casualties and losses of urban gas pipeline accidents can be reduced by fundamentally focusing on the prevention of gas leakage. Meanwhile, reasonable and effective emergency measures should be taken to effectively change the evolution direction of accident. Conclusively, the research results could provide reference for the emergency disposal of urban gas pipelines after accidents.