ObjectiveTo investigate the expression and resistant gene of integron in  multidrugresistant  Acinetobacter baumannii (MDRAb).Methods51 strains of MDRAb isolated from a hospital in AugustOctober  2012   were collected, antimicrobial susceptibility testing was performed. Class I(Int I)， II (Int II) and III (Int III) of integrase genes and integron variable region gene cassettes were detected by polymerase chain reaction (PCR)， and the homology of integron variable region was analyzed by detection results of  restriction fragment length polymorphism (RFLP)  and  DNA sequencing.ResultsPositive rate of integrase gene in MDRAb was 78.43%（40/51）. All genes belonged to Int I, while Int Ⅱ and Int Ⅲ were not found. Variable region cassettes were detected in 97.50% (n=39) of Int I， there were 5 types of integron gene cassettes: aacA4 in 14 strains， aacA4+catB8 in 22 strains，arr3+aacA4 in 1 strain， dfrA15 in 1 strain and  arr3 in 1 strain.ConclusionMDRAb isolated from this hospital may be related with Int I expression. Int I carried gene cassettes as follows: aacA4， aacA4+catB8， arr3+aacA4， dfrA15 and arr3.