Abstract: 【Objective】 To identify the individual phenolic composition and antimicrobial activity of sweet potato leaf polyphenols. 【Methods】 HPLC was used to identify the individual phenolic composition of sweet potato leaf polyphenols.Furthermore, oxford cup method and minimum inhibitory concentration method were used to determine the inhibitory activity of sweet potato leaf polyphenols on bacteria (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Proteus vulgaris) and mould (Aspergillus oryzae, Rhizopus oryzae). 【Results】 Sweet potato leaf polyphenols were mainly composed by 7 individual phenolic compounds.The order of inhibitory activity of sweet potato leaf polyphenols against bacteria and mould was: Gram-positive bacteria > Gram-negative bacteria > mould.Caffeic acid showed the highest antibacterial activity, with the minimum inhibitory concentration on Staphylococcus aureus and Bacillus subtilis 47 μg/mL, and it was true of that of ceftriaxone sodium. 【Conclusion】 Sweet potato leaf polyphenols have the potential to be used as a novel source of antimicrobial agent in the fields of food and medication.