Objective To study microbial killing efficacy of slightly acidic electrolyzed water (SAEW) in laboratory. Methods SAEW produced by hypochlorous acid water generator was selected to determine the microbial killing efficacy of different available chlorine concentration and different action time on bacterial propagules, spores and fungi. Results When the available chlorine concentration in SAEW was 34.3-118 mg/L, concentration of organic interfering substance bovine serum albumin(BSA) were 3.0% and 0.3%, the average killing logarithm values for Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were all >5.00 after 1.0, 3.0, 5.0, 10.0 minute contact time respectively, the average killing logarithm values for Candida albicans were all >4.00; when available chlorine concentration was 101-118 mg/L and concentration of BSA was 0.3%, the average killing loga-rithm values for spores of Bacillus subtilis var.niger were all >5.00 after 5.0, 10.0 and 30.0 minute contact time respectively. Conclusion Under specific experimental conditions, SAEW can meet the disinfection qualified stan-dard of disinfectant for bacterial propagules, spores and fungi.