ObjectiveTo investigate methicillinresistant Staphylococcus aureus (MRSA) infection in an intensive care unit (ICU), and evaluate the efficacy of intervention.MethodsFrom August 2008 to September 2010, all MRSA infection cases in ICU were collected, and all isolated MRSA strains were tested by molecular biology method, from september 2009 to September 2010, patients infected with MRSA were intervened and monitored, and compared with MRSA infection rate of one year before intervention, the efficacy of all measures was evaluated.ResultsThe detection rate of MRSA from ICU environment was 29.90%(87/291) before intervention and 7.90% (23/291) after intervention (χ2=45.910, P<0.05); the infection rate of MRSA in ICU patients was 35.87% (113/315) before intervention and 14.66%(51/348) after intervention (χ2=25.11, P<0.05). The risk factors for MRSA infection before and after the intervention were similar, the main risk factors were tracheal intubation and use of ventilator, neurosurgery operation, longterm application of broadspectrum antimicrobial agents, application of immunosuppressive agents, as well as nonisolation, et al．MRSA infection appeared mostly two weeks after patients’ admission, the longer time the patients were in hospital, the less effect of the intervention achieved.Conclusion ICUacquired MRSA infection rate is relatively high, early intensifying strategies, monitor, and control can reduce cross infection rate of MRSA.