Abstract: Aimed at the oil tank leaking dispersion accident and its consequence, a general methodology with quantitative simulation assessment is put forward in this paper. Through comparison, a relative suitable quantitative assessment model is occupied to evaluate the hazard consequence when oil tank is leaking. By the use of the simulating evaluation process, the harmful area can be calculated simply and shown in an ellipse area. The longest distance in the harmful explosion area and the harmful explosion area of the explosion hazard consistency, healthy harm consistency can be simulated and obtained combined with the application of an engineering case. Therefore, an applied methodology for simulating and evaluating the safety ofthe discharging dispersion process of oil tank is presented.