In this work, we fabricate silver nanoparticle arrays with a small size, high density, and controllable surface densities in a specific range using a rapid thermal annealing method. Based on the far-field optical reflection and transmission spectra of the silver nanoparticle arrays that are experimentally measured and according to a theoretical numerical conversion, the absorption, scattering, and extinction properties of the silver nanoparticle arrays are investigated. The results show that the resonance wavelength derived from the localized surface plasmon tends to redshift with an increase in surface density of the silver nanoparticle arrays (i.e., decreased nanoparticle spacing). In addition, the redshift is more pronounced for stronger coupling interactions between neighboring nanoparticles. This method provides a helpful reference for analyzing localized surface plasmon properties, primarily for small high-density metal nanoparticle arrays with non-negligible inter-particle coupling interactions.