Silver nanoparticles were synthesized by a totally green approach with silver nitrate (AgNO3) as precursor and ascorbic acid (Vc) as reducing agent. The nano-silver particles had narrow particle size distribution. The feature, structure and optical absorption properties of silver nanoparticles were characterized by X-ray diffraction (XRD), Raman spectra, ultraviolet visible spectrum (UV-Vis), scanning electron microscope (SEM) and transmission electron microscope (TEM). Surface-enhanced Raman scattering (SERS) on the prepared nano-silver particles as substrate was investigated by pyridine as the probe molecule. The results show that the detection limit is down to 10-10 mol·L-1. The variation tendency of Raman signal is stable with the change of the probe molecule concentration, which can be used for the study of the quantitative analysis.