Abstract: To improve therecrystallizing-fine effect of explosive HMX, a novel method——the spray-fine methodwhich combines chemical action with physical action——was presented. Jet-dispersing wasused in the mixed process of HMX solution and non-solvent and ultrafine particles wereprecipitated at a rapid velocity. 0.62～1.10μm particle of explosive HMX were preparedand the theoretical basis of the method and the mechanism of the spray-fine process wereelucidated. The recrystallizing-fine effect of explosive HMX can be distinctly improved byusing the spray-fine method and a narrow range of particle size distribution of explosiveHMX can be obtained.