ObjectiveTo investigate the distribution and change in antimicrobial resistance of Acinetobacter baumannii (AB) in healthcareassociated infection(HAI) in a hospital,so as to provide reference for rational use of antimicrobial agents.MethodsAB isolated from clinical specimens between January 2008 and December 2011 were identified with Vitek 2compact microbiology analyzer, antimicrobial susceptibility testing was performed by KirbyBauer disk diffusion method.ResultsA total of 597 AB isolates were isolated. The percentage of AB in gramnegative bacilli from 2008 to 2011 was 7.00%,8.35%,9.75%, and 12.66% respectively，percentage in 2011 rose obviously compared with 2008（χ2=32.77，P<0.05）. The major specimen was sputum (70.86%), AB distributed mainly in elderly ward（177 isolates，29.65%）, oncology department（115 isolates，19.26%）, and neurology department（93 isolates，15.58%）. Antimicrobial resistant rate of AB increased yearly during four years （P<0.05）,and resistant rate in 2011 to meropenem,cefoperazone/sulbactam and minocycline was low (8.56%,6.95%,5.35%,respectively).ConclusionInfection and antimicrobial resistant rate of AB rise constantly, strengthening the monitoring on AB is beneficial to guide rational use of antimicrobial agents in clinical practice and reduce the emergence and spread of drugresistant strains.