The present paper reports the FT-infrared spectra and FT-Raman spectra of the S-thyminyl-L-cysteine. The optimal concentration of the S-thyminyl-L-cysteine on silver sol is 10-4 mol·L-1. The interaction of S-thyminyl-L-cysteine with Ag nanoparticles was adsorbed by COO-, NH+3, S, and ring in the tilted way. Amino peak was enhanced in the acidic condition, carboxyl peak was enhanced in alkaline condition. Adsorption of S-thyminyl-L-cysteine on silver nanoparticles was mainly with carboxyl under the acidic condition and with amino under the alkaline condition. Other groups had no change at different pH. Establishment of this adsorption model provided important information and useful reference for further Raman spectra study of PNA, peptides and other biological molecules.