Biological decontamination means the removal of microorganisms from the inanimate object such as building or equipment. In this study, hydrogen peroxide vapor efficacy test using VHP 1000ED system(Steris LifeSciences) were conducted for G. stearothermophilus spore with agent materials(aluminum, stainless steel, poly-carbonate, viton, silicone, kapton and glass). Total recovered spores exposed to hydrogen peroxide vapor(1.0 g/min) during 7, 15, 30, 60 min were calculated. As a result, all agent materials were totally decontaminated within 60 min at 1.0 g/min concentration with 35% hydrogen peroxide vapor. Finally, we could confirmed that hydrogen peroxide vapor possess sporicidal capacity of G. stearothermophilus and found the optimum decontamination conditions with VHP1000ED system.