Abstract: Objective To study the status quo and homology of imipenem-resistant Acinetobacter baumanii and the genomic type of carbapenemase gene isolated from January 2006 to July 2009 in our hospitalMethods A total of 309 living,non-repetitive imipenem-resistant and sensitive Acinetobacter baumanii isolated from January 2006-July 2009 in our hospital were collected to identify their genomic types by amplified rRNA gene restriction analysis（ARDRA）.Minimum inhibitory concentrations（MICs） of meropenem,imipenem and other antibiotics were measured by agar dilution and interpreted according to the clinical laboratory standards Institute（CLSI） breakpoints.The homology of isolates was determined by both pulsed field gel electrophoresis（PFGE） and repetitive extragenic palindromic-polymerasechain reaction（REP-PCR）.b_laSHV,bl_aVEB,bl_aGES,bl_aIMP-,bl_aVIM-,bl_aOXA-23-like,bl_aOXA-24-like,bl_aOXA-58-like,and bl_aOXA-51-like genes for these strains were amplified and sequenced Results The CRAB strains resistant rate of cefoperazone/sulbactam,ceftazidime,cefepime,ciprofloxacin and amikacin was less than 10%.The CRAB strain resistant rate of minocycline was 41.2% and the susceptible rate of polymyxin B was 100%.The molecular epidemiology of CRAB typing by PFGE and Rep-PCR showed that 5 different clones were identified.The PFGE pattern A1 was found in 17 different wards,the other clones were named A2,B,C,D and E clones.The multiplex PCR assay amplified fragments of bla_OXA alleles encoding each of the 4 subgroups of OXA carbapenemases in Acinetobacter spp.alleles encoding bla_OXA-23-like and bla_OXA-51-like were detected in 147 of 274（53.6%） isolates.Genes encoding OXA-23,OXA-66,OXA-69,OXA-72,OXA-58 and PER-1 enzymes were detected.Sequence analysis of the products from different wards and MICs for the bla_OXA-51-like amplicons（15 cases） identified bla_OXA-66 in 14 cases and bla_OXA-69 in 2 casesConclusion A1 clone spread is the main reason for the increased Imipenem resistance in Chaoyang Hospital.The most prevalent carbapenemase is an OXA-23/OXA-51-like enzyme.