Study of light scattering by nanoscale structures is essential to evaluate the radiative heat transfer in silica aerogels. For the purpose of simplification and feasibility regular structures are proposed to substitute irregular structures in silica aerogels to obtain average results of light scattering. The differential scattering cross section increases with density and decrease dramatically with wavelength in the visible spectrum. An inverse power-law relation can be observed between the differential scattering cross section and the incident wavelength. Furthermore, a power-law relation can be obtained for dimensionless scattering cross section and density. These findings are very helpful to understand the influences of structural parameters on light scattering.