A dual-wavelength Raman-Mie lidar technique and system are proposed in this paper to provide sufficient aerosol information for the solution of the radiative transfer equation. First, a high-performance four-channel spectroscopic system is designed to extract the Mie-Rayleigh scattering echo signals with center wavelengths of 354.7 nm and 1064.2 nm and Raman scattering echo signals of 386.7 nm and 852.7 nm for the fine detection and inversion of atmospheric aerosols. Then, the system is applied for experiments under different weather conditions, and the list of actual atmospheric aerosol state parameters is formed on the basis of the aerosol multi-parameter profiles obtained by inversion, which is composed of 33-layer optical thickness, single scattering albedo, and scattering phase functions. The list is used as the input file of actual atmospheric aerosols for the Santa Barbara DISORT atmospheric radiative transfer (SBDART) model. Finally, the radiative transfer equation is solved, and the calculation results of the actual atmospheric scattered radiance distribution of 33-layer and the direct and diffuse solar irradiance are obtained. By analyzing the actual atmospheric scattered radiance under different weather conditions, this study verifies the decisive influence of the atmospheric aerosol on atmospheric scattered radiance. The experimental results reveal that the average relative error of the total irradiance measured by the system and the ground meteorological station is 8.2%, and the correlation coefficient reaches 0.98.