Abstract: ObjectiveTo study the geunicidal efficacy of ortho-hthaladehyde disinfectant and its related properties.MethodsB actericidal quantitative suspension test, stinulating practical conditions and field test, stability test and metal corrosion testwere used.ResultsThe logarithm reduction of Escherichia coli and Staphylococcus aureus exposed to the disinfectant solution containing 0.53% ortho-phthalaldehyde fort.5 min were larger than 5.00, and that of Candida albicans and M.Chelonae subsp, abscessus were larger than 4.00.It could reach a high disinfection level in endoscope disinfection stinulating practical test and field testes ith 0.53% ortho-phthalaldehyde for 5m in.There was no corrosion for stainless steel, carbon steel, copper and alum inum after inmersing in the disinfectant solution containing 0.53% ortho-phthalaldehyde for 72h.The content of ortho-phthalaldehyde declined 2.08% after the product was stored in 37℃ temperature and constant humidity condition for 90 days.The validity duration was at least 2 years.ConclusionThe endoscope disinfection of 0.53% or tho-phthalaldehyde for 5m in could satisfy high level disinfection dem and The disinfectant was stable and ahost no corrosion effect, so it could be used for endoscopic disinfection.