Abstract: Objective To investigate the relationship between nasal colonization of Staphylococcus aureus(SA) and nosocomial infection in intensive care unit(ICU), and observe the therapeutic effect of Anerdian Ⅲ in nasal decolonizaion. Methods Bacterial cultures were made by means of nasal swabs among inpatients whom the occurrence of nosocomial infection were observed. Patients with SA colonization were randomly divided into two groups:control and treatment. Control group were given regular treatment, and treatment group were administered Anerdian Ⅲ in addition to regular treatment. Then the clearance rate of SA and the occurrence of nosocomial infection of two groups were observed. Results A total of 751 patients were enrolled, of whom 108(14.4%) were with nosocomial infection and 85(11.3%) with SA nasal colonization. Methicillin resistant Staphylococcus aureus(MRSA) was detected in 33 patients(4.4%). The nosocomial infection rate of patients with MRSA colonization was 51.5%, which was significantly higher than those in patients with other bacterial colonization(P<0.05).The SA clearance rate in treatment group was significantly higher than that in control group(81.4% vs. 42.8%,P<0.05).The nosocomial infection rate in treatment group was significantly lower than that in control group(16.3% vs. 40.5%,P<0.05).After decolonization treatment,the nosocomial infection rate of patients with MRSA colonization was significantly lower than that in control group(25.0% vs. 76.5%,P<0.05). Conclusion The incidence rate of nosocomial infection in patients with MRSA nasal colonization is markedly increased in ICU, and the decolonization treatment by Anerdian Ⅲ increases the clearance rate of nasal SA and decreases the incidence rate of nosocomial infection.