Surface-enhanced Raman scattering（SERS) presents a significant enhanced effect.The surface of Ag electrode was pretreated by electrochemical method to obtain a SERS active substrate.The concentration of salicylic acid（SA) absorbed on this rough Ag electrode could be determined by the corresponding SERS spectra.Potassium thiocyanate was selected as the internal standard and the relative intensity was formed by aromatic ring breathing（1 036 cm-1) of SA and characteristic peak（2 120 cm-1) of SCN-.A good linear relationship was obtained between the relative intensity and concentration of SA in the range of 4×10-6-3×10-4 mol/L，with a correlation coefficient of 0.993 1.The detection limit was 2.04×10-6 mol/L and the recoveries were in the range of 85.4%-114.6%.The interference experiments were also considered.With the advantages of convenience，no interference of internal substance，green and harmlessness，the method could be extended to the determination of other special substances.