Au10Cu90 and Au76Cu24 nanoparticles (NPs) were directly fabricated on a glass substrate by spark discharge deposition technique. The prepared NPs were characterized by FE‐SEM, and XPS techniques. The substrate composition was controlled by simply changed the electrode type that connected to a high voltage power supply. The generated substrates were evaluated of surface‐enhanced Raman scattering (SERS) by using crystal violet as a molecular probe. The Au76Cu24 substrate showed the highest SERS signals, with a limit of detection could reach to 1 × 10−12 M, and enhancement factor of 2.8 × 108. The high SERS performance of this substrate could be attributed to the high electromagnetic field generated between the connected networking NPs and the chemical enhancement provided by the small amount of CuO.