A method adopting entropy weight and fuzzy comprehensive evaluation to solve the problem in quantitative disposal of qualitative index in the security risk assessment of scraped ammunition is proposed. The method can be used to analyze the existing danger quantitatively and qualitatively and confirm the risk level of the system. It can reflect the system safety level objectively for avoiding the influence of subject factors. Finally, the method is verified by the piratical example and can be used on scraped ammunition disposing system efficiently.