The interaction between human serum albumin (HSA) and salvianolic acid A (SA-A) was investigated by means of spectroscopy. The thermodynamic parameters ΔH and ΔS, had been calculated to be 148.94KJ·mol-1 > 0, and 640.85 J·mol-1·K-1 > 0, respectively. The distance between the donor (HSA) and receptor (SA-A), r, was obtained to be 2.49nm according to Förster's non-radiative energy transfer theory. The experimental results revealed that SA-A could quench the fluorescence of HSA by a static quenching mechanism. Furthermore, the binding constants between HSA and SA-A were obviously affected by metal ions, decreased in the presence of Co(Ⅱ) and Mg(Ⅱ), increased with Ni(Ⅱ) and Zn(Ⅱ), and no change with Cu(Ⅱ). The interaction between SA-A and HSA was driven mainly by hydrophobic force.