Abstract: The suppression pool can reduce the peak pressure of the containment in the early stage of the loss-of-coolant accident（LOCA）. The main influencing factors of the pressure suppression ability are the submergence depth of pipe,steam flow rate and non-condensable gas content. The combination of parameters of influencing factors is changeable,resulting in a huge number of tests and data processing required for the sensitivity analysis. The orthogonal experiment can not only reduce the number of experiments,but also intuitively analyze the order of the influencing factors. Therefore,this paper adopts the orthogonal experiment. The method is adopted for the sensitivity analysis on the influencing factors,taking the peak pressure of the suppression pool as the index,and through the orthogonal experiment range analysis,the study showed that the key factors that influence the peak pressure of the suppression pool are,respectively,the submergence depth of pipe,steam flow rate,and the non-condensable gas content with their sensitivities decreasing in sequence.