Objective: To investigate the clinical distribution and drug resistance of pathogens of acinetobacter baumannii (AB) strains isolated from the First Affiliated Hospital of Nanjing Medical University from 2012 to 2014. Methods: Automatic detection machine of VITEK-2 compact was used for identification of bacteria, as well as the drug susceptibility of the AB was performed by using disc agar diffusion (K-B method). All data were analyzed by WHONET5.6 or SPSS 19.0. Results: From 2012 to 2014, the separation rates of AB were 13.7%, 11.5% and 12.2%, respectively, higher than pseudomonas aeruginosa, lower only to Escherichia coli. The AB were mainly isolated from the department of intensive care unit (ICU, 44.6%), surgery (28.4%), and internal medicine (22.5%). A total of 79.2% isolates were from the respiratory tract specimens. The resistance rates to many kinds of antibiotics of AB strains were higher than 70.0%. The lower resistance rates of the AB to minocycline, amikacin, were 43.4%~55.8% and 50.1%~58.4%, respectively. There was a decrease in trend percentages during three years from 2012 to 2014. There were differences among the resistance rates of the AB isolated from different specimens and different departments. Conclusion: AB had been the most frequent non-fermentative pathogen causing clinical infection and the respiratory tract infection was dominant. Though AB was highly resistance rate to clinical antibiotics, it had a downward trend. The use of antimicrobial drugs should continue to standardize.