ObjectiveTo investigate the clinical distribution and change in antimicrobial  resistance of  Acinetobacter baumannii （A.baumannii）from a hospital between 2011 and 2013,  so as to provide guidance for clinical treatment. MethodsSources and antimicrobial susceptibility testing results of A.baumannii from a hospital were analyzed statistically. ResultsA total of 14 705 bacterial isolates were isolated in 2011—2013，13.59%（n=1 999）of which were A.baumannii isolates, the percentage of A.baumannii  in isolated pathogens in 3 years was 12.74%,13.05%, and 14.85% respectively，which showed a rising trend  （χ2=9.458，P=0.002）. The main specimen was sputum (n=1 541, 77.09%), bacteria were mainly isolated from  patients in respiratory disease department（21.71%）, surgical intensive care unit (16.26%), and emergency intensive care unit (8.26%). Antimicrobial resistance rates of  A.baumannii  increased year by year(all P<0.05); multidrugresistant and extensively drugresistant A.baumannii also increased year by year (all P<0.001).  ConclusionIsolation rate and antimicrobial resistance rate of A.baumannii strains increase year by year, multidrugresistant and extensively drugresistant A.baumannii strains are obvious, which should be paid more attention in clinical department.