Objective To investigate the homology of Acinetobacter baumannii (A. baumannii) isolated from patients and environment in intensive care unit(ICU) of a hospital. Methods 180 sepcimens from patients and environment in ICU of a hospital in Jiangsu Province were performed A. baumannii isolation, antimicrobial susceptibility analysis and pulsed-field gel electrophoresis (PFGE) typing. Results 180 specimens were isolated 41 strains of A. baumannii, including 9 clinical strains and 32 environmental strains. Antimicrobial susceptibility testing result showed that resistance rates of A. baumannii to other antimicrobial agents were all higher than 70%, except for levofloxacin (34.1%). 41 strains of A. baumannii were classified into 19 PFGE genotypes, there were at least 2 strains in each of the five types(type I, M, N, O, and P), the others were all one type; there were 16 strains of type P, 5 of which were from patients with HAI, and the rest were from patients' ventilators, treatment vehicles and the surrounding, the detection time span of this type of A. baumannii was 141days. Conclusion A. baumannii isolated from patients and environment in ICU of this hospital has homology, and there is transmission in hospital and epidemic of HAI. Supervision of disinfection measures should be strengthened in order to avoid the occurrence and epidemic of HAI as far as possible.