The effects of temperature, BSA concentration and common ions on the interaction between astilbin and bovine serum albumin (BSA) were investigated by fluorescence method. The results showed that astilbin could quench the fluorescence of BSA through static quenching, which reflected the interaction between the two molecules. The thermodynamic parameters including binding constants, enthalpy change, entropy change and free energy change were calculated. The binding constant increased slowly with the increase of temperature, and the positive enthalpy and entropy change revealed that hydrophobic force played an important role in the interaction between the two molecules. Common ions, such as Ca2+,Mg2+,K+,SO42- and had little effects on the interaction between astilbin and BSA. The results of synchronous fluorescence spectra showed that astilbin could increase the polarity of hydrophobic environment near the tryptophan residue of BSA.