Objective To investigate the molecular epidemiological characteristics of extraintestinal pathogenic E.coli (ExPEC) clinical isolates by firstly detecting their 30 known virulence factors and phylogenetic groups A,B1,B2 and D,secondly analyzing the relationship between these virulence factors and phylogenetic groups.Methods A total of 210 ExPEC clinical isolates were investigated.Multiplex PCR was performed to detect the 30 virulence factors among the 133 E.coli strains isolates.For the virulence factors statistical analysis,the comparisons of proportions between groups were evaluated by using Fisher's exact test.Results In this study we found that,the following virulence factor genes fimH,fyuA,traT,iutA,kpsMT Ⅱ and PAI have a higher detection rate 79％,75％,74％,73％,62％ and 46％ perspectively.For all isolates strains,24％,11％,29％ and 36％ were assigned to the phylogroup A,B1,B2 and D,respectively.pagG alle Ⅱ,papA,sfa/focDE,hlyA,rfc,cnfl,cvaC and FocG were only associated with phylogroup B2.papGflanking Ⅱ and Ⅲ,afa/draBC,kpsMT Ⅲ and nfaE were only linked to phylogroup D.In contrast,fyuA,PAI,K 5,papEF,K 1 and papC were associated with phylogroup B 2 and D.Conclusion The phylogenetic groups of ExPEC belong mainly to the group B2 and D.The virulence factors and phylogenetic groups of extraintestinal pathogenic E.coli are closely related.