Abstract: Large steel storage tanks are vulnerable to damage in explosion accidents, and the safety problems related with the explosion resistance safety of such structure are concerned. In this paper, the motion differential equations for the structure of storage tank were established according to the cylindrical shell theory. Then, the damage process of the fixed-roof storage tank with volume of 2×10⁴ m³ by the explosion was simulated by using the non-linear finite element calculation software LS-DYNA. And finally, the reliability of the numerical simulation results was verified by performing damage simulation test on the scaled model. It is shown that the fixed-roof tank under the effect of explosion presents the characteristics of elastic-plastic dynamic response. Due to axial tensile internal force of the tank, stress concentrates firstly on the wall at the top of the tank, leading to the failure of the structural strength. And as a result, the failure mode of concave buckling at the tank wall facing the blast and at the partial fixed roof is formed. Besides, under the effect of the composite impulse of explosive blast and liquid, the adjacent tank wall undergoes the deformational event in the direction of blast loading under the driving of the failure region, and eventually the tank is destabilized. The research results can provide the reference for the explosion resistance design of large steel oil storage tanks.