The binding pattern of Ethaselen to bovine serum albumin （BSA） was studied by fluorescence spectroscopic technique and Autodock 3.0.5 analysis. The result showed that the binding constant K of Ethaselen and BSA is 3.5×10^4L/mol and the number of binding sites n = 0.9. The binding between Ethaselen and BSA or human serum albumin （HSA） is mainly through hydrophobic interactions.
