Abstract: OBJECTIVE To investigate the outbreak of suspected pan-drug resistant Acinetobacter baumannii (PDR-AB) infection in ICU, and to study the cluster-based strategy for preventation and control of pandrug resistant A baumannii nosocomial infection, so as to guide the implementation of preventation and control measures for nosocomial infections. METHODS We conducted the survey by means of molecular epidemiological analysis combined with environmental hygiene monitoring to collect more information about the isolation and infection of PDR-AB in ICU from Feb. to Apr. 2018. Environmental microorganism sampler was used to collect samples from the environment and items with suspected contamination for identification and drug sensitivity test.The homology of strains isolated from the patients and environment were studied using PFGE technique. RESULTS In Mar. 2018, there were 7 cases of A baumannii infection or colonization in ICU, with the new infection rate of 10.14%. PDR-AB were isolated from the head cushion towel, bed tail plate and bed bar of patients with PDR-AB colonization or infection, table top of nurse station, care clothing of the medical staff and the bronchofiberscope after cleaning and disinfection. Drug sensitivity test showed that the resistance spectra of the 27 strains of PDR-AB isolated from ICU patients and the environment were basically the same, and the PFGE results revealed that the PDR-AB strains isolated from the patients, environment and bronchofiberscope belonged to the same subtype. CONCLUSION The cloned strains of PDR-AB are highly homologous to each other among patients, the environment and bronchofiberscope. The outbreak situation can be effectively controlled by strengthening the aseptic concept of clinical medical and nursing staff, isolation of patients, strict cleaning and disinfection of the environment and medical equipment.