Abstract: Objective To investigate the incidence of nosocomial infection in ICU, mortality rate of infected patients, the risk-factors and strategies of nosocomial infection. Me thods We retrospectively analyzed all ICU patients' medical records from August 2015 to August 2016, and the incidence of nosocomial infection. All patients were retrospectively analyzed, the infected patients as the observation group, the same period without infection as a control group. We compared the gender, age, APACHEII score, admission ICU time, plasma albumin levels, whether surgery, whether there were disturbance of consciousness, whether invasive operation, whether the use of antibiotics, whether combined with other underlying diseases and other risk factors between the two groups of patients. We also compared the differences in mortality between the two groups of patients. Re s ults The incidence of nosocomial infection was 29.41%. There were significant differences in APACHEII score, ICU time, disturbance of consciousness, underlying disease, age and invasive operation (P <0.05) . There was no statistically significant difference in sex, plasma albumin level, operation and prophylactic use of antibiotics significance. The mortality rate (40%) was significantly higher in hospital patients than in the control group (16.7%) (P<0.05) . Conclusion Severity of illness, ICU stay, unconsciousness, underlying disease, age, invasive procedures have a significant impact on the incidence of nosocomial infections, gender, serum albumin level, surgery, prophylactic use of antibiotics have no effect on the incidence of nosocomial infections.