In this work,nanopillar-forest based surface-enhanced Raman scattering substrates were fabricated using a novel approach.The key technique of the approach is taking advantage of convexes on Poly-Si surfaces as support structures in sidewall technology.The tip-diameters of the fabricated nanopillars are from 5 to 10 nm,heights are of several microns,and density of the nanopillar-based forests is around 20/μm2.In these nanopillar forests,there are plenty of nanoscale gaps.When covered with a thin layer of noble metal,the nanopillar forests exhibit a high SERS-active capability.Primary measurement results demonstrate that the nanopillar-forest based SERS substrates have an enhancement factor of an order of 4.62×106.It is expected that such SERS substrates may have applications in biological monitoring and chemical detection. In this work, nanopillar-forest based surface-enhanced Raman scattering substrates were fabricated using a novel approach. The key technique of the approach is taking advantage of convexes on Poly-Si surfaces as support structures in sidewall technology.The tip-diameters of the fabricated nanopillars are from 5 to 10 nm, heights are of several microns, and density of the nanopillar-based forests is around 20 / μm 2 .In these nanopillar forests, there are plenty of nanoscale gapss.When covered with a thin layer of noble metal , the nanopillar forests exhibit a high SERS-active capability. Primarily measurement results demonstrate that the nanopillar-forest based SERS substrates have an enhancement factor of an order of 4.62 × 106. It is expected that such SERS substrates may have applications in biological monitoring and chemical detection.