The clinical characterization of Bacillus amy-loliquefacien contaminating 75% alcohol disinfectants were studied. The bacteria were cultured and observed by using bacterial examination under the hospital infec-tion monitor. According to the regulations, the resistance of bacterial to physical and chemical factors was tested. Drug sensitivity tests for 20 commonly used medicines were carried out using a K-B method. The bacterial plas-mids were analyzed using the Biboim method. The bac-teria were found after being cultured in the clinically-used 75% alcohol disinfectant fluid. Their total number was more than 800 cfu/mL and they were identified as Bacillus amyloliquefacien. The bacteria were also found to be resistant to boiling for 5 min. It grew well in 95% alcohol disinfectant and was insensitive to 84 disinfectant fluids containing chlorine (1000 mg/L) and such disinfec-tants as ozone. They were able to be sterilized better through routine ultraviolet exposure for 30 min or gas pressure. The bacteria contained a 2.5 kb plasmid and were sensitive to 13 drugs and insensitive to 7 drugs of the 20 drugs tested. It was suggested that alcohol dis-infectant fluid was easily contaminated by Bacillus amy-loliquefacien, and the bacteria was resistant to disinfectant fluids such as alcohol and 84 disinfectants.