Abstract: OBJECTIVE To understand the effects of disinfection of medical instruments with different methods and disinfectants so as to determine the better cleaning method. METHODS The contaminated instruments were soaked and cleaned by respectively using multiple enzyme cleaning fluid ( the group Ⅰ) , cleaning liquid containing chlorine ( the group Ⅱ) , and sterile water ( the group Ⅲ ). The cleaning effects were observed and evaluated by using visual inspection method and five times magnifying glass with light source. The instruments were soaked in glutaraldehyde for disinfection after cleaning, the instruments were sampled according to the Disinfection Technical Specifications 2002 edition 4.7.4.1.3, and the test results were observed and compared. RESULTS The qualified rate of cleaning of the group Ⅰ was 100.0% by visual inspection, 100.0% by five times magnifying glass with light source. The qualified rate of cleaning of the group Ⅱ was 100.0% by the visual inspection, 97.5% by five times magnifying glass with light source. The qualified rate of cleaning of the group Ⅲ was 90.0% by visual inspection, 75.0% by five times magnifying glass with light source. The disinfection effect of the multiple enzyme cleaning fluid was the best after cleaning with glutaraldehyde, followed by the cleaning liquid containing chlorine, the sterile water the poorest. The duration of continuous use of glutaraldehyde disinfectant was the shortest in the sterile water group. CONCLUSION The cleaning effect of the multiple enzyme cleaning fluid is significantly better than that of other two cleaning methods..