The cumulative incidence rate of nosocomial infection was 7.3% and the incidence density was 7.48/1000 patient-days in which nosocomial pneumonia accounts for 67.6%, septicemia10.6%, conjunctivitis 7.74%, meningitis 6.33%, enterocolitis 4.93%, urinary tract infection 1.4%, surgical site infection 0.7% and skin infection 0.7%.