Copper nanoparticles grafted on a silicon wafer are fabricated by reducing copper ions with silicon–hydrogen bonds and assembling them in situ on the Si wafer. The nanoparticles, with an average size of 20 nm, grow uniformly and densely on the Si wafer, and they are used as substrates for surface-enhanced Raman scattering. These substrates exhibit excellent enhancement in the low concentration detection (1 × 10−9 M) of rhodamine 6G with an enhancement factor (EF) of 2.29 × 107 and a relative standard deviation (RSD) of <20%. They are also employed to detect sudan-I dye with distinguished sensitivity and uniformity. The results are interesting and significant because Cu substrates are otherwise thought to be poor. These effects might provide new ways to think about surface-enhanced Raman scattering based on Cu substrates.