Abstract: OBJECTIVE To explore the causes of hospital aggregated infection caused by multidrug-resistant Acinetobacter baumannii and put forward the prevention and control measures for the infection. METHODS The clinical data were collected from 10 patients with hospital cluster infection caused by multidrug-resistant A.baumannii who were treated in hospitals from Jan 2016 to Mar 2016, the result of epidemiological investigation was analyzed, the specimens were detected, and statistical description was performed. RESULTS The infection occurred in the 10 patients before and after the spring festival, all of whom were hospitalized in the ICU and had lower respiratory tract infection (including 8 cases of VAP); 6 patients were aged more than 65 years old, accounting for 60%, all of the 10 critically ill patients underwent endotracheal intubation and mechanical ventilation, one of whom received tracheotomy after the endotracheal intubation for 14 days. Totally 8 patients were treated with antibiotics for more than one week, accounting for 80%; the length of ICU stay varied from 3 to 27 days, with the medial length 10.5 days. CONCLUSION The incidence of multidrug-resistant A.baumannii is associated with the age, underlying disease, invasive operation, use of antibiotics, length of ICU stay, isolation and disinfection measures, hand hygiene, monitoring of nosocomial infection in ward, and biochemical characters of A.baumannii.