Objective: In order to study the antibacterial activity of the Broussonetia papyrifera leaf extracts. Method: The active components of B. papyrifera leaf were extracted by organic solvent

and silica gel column chromatography. The antibacterial effect in vitro of the extracts above onseveral pathogenic bacteria stains such as Staphylococcus aureus

Pasteurellamultocida

Escherichia coli

Salmonolla sp and Riemerella anatipestifer were observed

and the minimum inhibitory concentration(MIC)

minimal bactericidal concentration(MBC) were also determined. Result: The result indicated that water

70% ethanol and 50% acetone extracts of B. papyrifera leaf extracts showed better antibacterial activity

and the MIC of the water extract agaist S. aureus

Pasteurellamultocida

E. coli and Salmonolla sp were 6.75

25

6.75

12.5 g·L-1 respectively. The bacteriostatic constituents mainly exist in ethyl acetate and n-butanol extract as the B. papyrifera leaf water extract were extracted by organic solvent step by step. Moreover

3 components had antibacterial activity agaist the pathogenic bacteria were isolated from ethyl acetate and n-butanol extract respectively. Conclusion: B. papyrifera leaf contains a variety of antibacterial ingredients

which vary in physicochemical properties

antibacterial activity and mechanism; further study on separation

identification and chemical structure determination of the compounds is expected to provide the basis for development of new antimicrobial drugs.