For the design of fire-extinguishing ammunition,the mathematic relationship between dynamic action area and stand-off distance was presented. Based on the engineering requirements from optimization design of fuse-warhead cooperate on the fire-extinguishing ammunition,the experiments of static action on the warhead and dynamic dispersed on the simulation ammunition were conducted. The processes of static action and dynamic dispersed were analyzed according to the experimental results. A computational mathematics method on dynamic dispersed processes for the fire-extinguishing ammonization was set up,the correlation between dynamic dispersed area of the fire-extinguishing ammunition and the stand-off distance was obtained by calculation. The calculated results agree well with the experimental results.