Abstract: Objective　To identify the horizontal transfer of multi-drug resistance related gene fragment and to explore the location of transferred gene fragement.Methods The study began withen richment culture of the positive clone,fo l2 lowed by the extraction of plasmid and PCR.The product of PCR was purified by gel purification kit and labled.Finally the dot hybridization with genome DNA and plasmid of E1667,transfer strain,and Z23 was done.Results The probe specific to multi-drug resistance ralated gene fragment was hybridized.E.667 and transfer strain's genome DNA and plasmid all showed positive hybridization signal.Whereas Z23’s genome DNA and plasmid both had negtive hybridization signal.Conclusion The multi-drug resistance related gene fragment was transferred from E.667’s plasmid to Z23’s plasmid.