Abstract: With the basis of gas explosion theory, high accuracy WENOscheme is adopted for numerical simulation of methane explosion in variable cross-section tube. Influence of variable cross-section tube on flame propagation of methane explosion is addressed. It is found that, variable cross-section tube results in decrease of the intensity of methane explosion. On this basis, the influence of obstacle, wall and three shock wave structure on re-initiation is analyzed. The results suggested that the shock reflection on the wall and collision of triple points can induce re-initiation. These conclusions provide valuable theoretical basis for prediction of methane explosion, safety assessment and prevention of fire and explosion.