Abstract: ObjectiveTo compare the germicidal efficacy between ortho-phthalaldehyde and potent iated glutaraldehyde in disinfection of spores of Bacillus subtilis var.niger.MethodsCarrier quantitative disinfection test was used to make comparison of the two disinfectants in their gerimicidal efficacy and constinuous stability.ResultsThe logarithm value of disinfection spores of Bacillus subtilis var.niger exposed to 0.53% ortho-phthalaldehyde for 3 h was 3.21 and that of 10 h was higher than 6.10.The same disinfection logarithm value of 2.18% potentiated glutaraldehyde for 3 h was higher than 6.10.In continuous stability test,the germicidal efficacy of 0.53% or tho-phthalaldehyde in disinfection of the spores was effective after 7 and 14 days of contionous use.ConclusionAt the same concentration,the sporicidal efficacy of ortho-phthalaldehyde was weaker than that of potentiated glutaraldehyde,but or tho-phthalaldehyde still is of high germicidal efficacy and comtinuous stabinty for endoscopes.