In this study,oleanolic acid derivatives were designed and synthesized from oleanolic acid,which is a natural pancreatic lipase inhibitor. The structures of synthesized derivatives was characterized by ~1 H NMR,~(13)C NMR and MS.Their inhibitory effects on pancreatic lipase were tested and their interaction mechanisms were analyzed. Results showed that two new oleanolic acid derivatives: oleanane-28-β-lactone( IC_(50): 16. 4 μmol/L) and oleanane-28-α,β-unsaturated ester( 18. 5 μmol / L),had higher inhibitor...