In the non-aqueous acetonitrile solution, recurring to the confocal Raman system, we studied the intensively chemical adsorption of pyridine(Py) on the surface of platinum electrode utilizing surface-enhanced Raman scattering (SERS). With the change in the potential, the quantity and adsorptive orientation of the adsorbate also change, interacting on the surrounding molecules. In the present paper, the adsorption of Py on the surface of platinum electrode was not only clearly observed, but also the dissociation of acetonitrile was discovered simultaneously. And the more complicated double layer in the non-aqueous solution than in the aqueous one explains the differences of the results between the non-aqueous and aqueous solutions.