Objective To understand the drug resistance situation of 84 strains of Acinetobacter Baumannii (ABA) isolated from the lower respiratory tract samples in ICU patients to provide a basis for the rational use of antibacterial drugs in clinic .Methods Eighty-four strains of ABA were retrospectively analyzed .The VITEK2-Compact automatic microbiological analyzer was adopted to conduct the bacterial identification and drug susceptibility test .The software Whonet5 .6 was used for conducting the statistical analysis .Results Eighty-four strains of ABA had strong drug-resistance . The resistance rate of nitrofurantoin was highest (100 .00% ) ,followed by cefotetan (98 .81% ) and aztreonam(80 .95% ) .The resistance rate of beta lactam antibacterial drugs was>75 .00% ,and which to imipenem was 76 .19% .The sensitive rate of 13 kinds of common antibacterial drugs was < 30 .00% . MDR ,XDR and PDR strains were 67 strains ,64 strains and 26 strains respectively ,which accounted for 79 .76% ,76 .19% and 30 . 95% respectively .The non-sensitivity rates of multi-drug resistant strains either to MDR or XDR was >90 .00% in non sensitive rate of common antimicrobial agents .Conclusion ABA is the major pathogen .The laboratory should strengthen the analysis and drug sensitivity monitoring of ABA resistant strains in ICU .At the same time ,ICU should strengthen the disinfection and isolation to avoid the outbreak of nosocomial infections .