Abstract: A method for the isolation and purification of ginkgolic acids in the bark of Ginkgo Biloba. L and the antibacterialactivity of ginkgolic acids were studied in this paper. The results showed that the non-polar D4020 resin and weak polar AB-8 resin all had excellent adsorption properties. Through both resins adsorbing with different concentration ethanol gradsdesorbing, the obtained ginkgolic acids products had 90% purity and 0.91% yield. Using the resins to purify ginkgolic acids wasan effecfive method that had lower cost and higher efficiency. Ginkgolic acids were identified to comprise five isomers (C13:0, C15:1,C17:2,C15:0, C17:1) by LC/DAD/MS analysis. The content of C15:1 was the highest and C17:1 was the next Ginkgolic acids werefound to be bactericidal against B.cereus, B.subtilis and S.aureus, but not bactericidal against E.coli.The alkyl side-chain of ginkgolicacids played an important role in antibacterial action of ginkgolic acids.

Key words: ginkgolic acids, isolation, identification, antibacterial