Abstract: In order to study the mechanism of binding and transport between kudinoside L,kudinoside N and bovine serum albumin(BSA)and the secondary structure of BSA at different temperatures. The fluorescence quenching mechanism between kudinoside L,kudinoside N and BSA was studied by fluorescence spectroscopy. The change of secondary structure of BSA was studied by circular dichroism.The results showed that both kudinoside L and kudinoside N could effectively quench the endogenous fluorescence of BSA. The quenching type was dynamic quenching,the intermolecular force was mainly hydrophobic,and the two compounds formed a binding site with BSA. In addition,after kudinoside L combined with BSA,the α-helix and β-sheet content in BSA increased;after kudinoside N combined with BSA,the α-helix and random coil content in BSA decreased. It was proved that the internal structure and environment of BSA changed after the combination of the above two saponins with BSA.