The sulfuryl fluoride fumigation with the concentration of 20g/m3 in five-side-sealed space loaded with stacks of bagged flour was researched. The effect of the fumigation and its permeability was analyzed. The results showed that all of the different life stages of pests were killed after 52h. The half life during fumigation was 1.6h because of the poor gas tightness, which indicated that the five-side sealing mode was not suitable for sulfuryl fluoride fumigation. Sulfuryl fluoride could permeate into the depth of 1.5m in the stacks to kill the adult pests in the depth of 0.6m after fumigation for 52h. The tolerance of Tribolium castarnum(Herbst), Cryptolestes ferrugineus (Stephens), Sitophhus sryzae(Linnaeus), Oryzaephhus surinamemis(Linnaeus) were different.