ObjectiveTo study the biofilm forming ability and effect on antimicrobial resistance of 50 uropathogenic Escherichia coli (UPEC) strains isolated from clinic. MethodsScreening of biofilm formation was performed by crystal violet staining, the susceptibility of 50 UPEC isolates to 8 kinds of antimicrobial agents was determined by KirbyBauer method, the correlation between antimicrobial resistance and biofilm formation was analyzed statistically.ResultsAmong 50 UPEC isolates, 34(68.00%) were biofilmpositive strains. All UPEC strains showed different resistance to 8 kinds of antimicrobial agents; the resistant rates of biofilmpositive strains to ampicillin (76.47%) and gentamicin （55.88%) were significantly higher than those of biofilmnegative strains (43.75%，18.75% respectively) (P<0.05). ConclusionThe formation of biofilm in UPEC is common, the formation of biofilm correlats with its resistance to ampicillin and gentamicin.