Based on the substrate of silica and different types of slides, the effect of refractive index of substrate on fabrication and optical properties of hybrid Au- Ag triangular periodic nanoparticle arrays is systematically investigated. The optical spectrum of localized surface plasmon resonance (LSPR) simulated by discrete dipole approximation (DDA) numerical method shows that the nanoparticle arrays can obtain better refractive index sensitivity (RIS) and figure of merit (FOM), when refractive index of substrate is 1.43 and 1.68, respectively. The nanosphere lithography (NSL) is used to fabricate the periodic nanostructure arrays. The experimental results demonstrate that when refractive index of substrate is 1.43 and 1.68, nanoparticles and substrate have better adhesive ability. Meanwhile, the nanoparticles both form a large-scale monolayer array with the hexagonally close-packed structure.