A one-step microwave-assisted method was used for the synthesis of silver nanoparticles, and the corresponding nature and structure of silver nanoparticles were characterized by UV-Vis absorption spectroscopy, transmission electron microscopy (TEM), and atomic force microscopy (AFM). Raman scattering activities of silver nanoparticles with different reaction times were checked by using rhodamine 6G (R6G) as a probe molecule. The results showed that the intensity of surface enhancement Raman scattering (SERS) signals could be increased by silver nanoparticles. And then we made a comparison on SERS spectra of R6G molecules adsorbed on three kinds of silver nanoparticles to investigate the effect of surface enhancement Raman. Meanwhile, we have also performed substantially studying of the mechanism in the process of enhancement by silver nanoparticles.