The inverse problem on simultaneous determination of microstructure characteristics and the refractive index of atmospheric aerosol from simultaneous measurements of the spectral transmission and solar aureole brightness is considered. To describe microstructure of the medium, integral functions of the particle size distribution were used. The similitude relationships have been derived, which the microstructure characteristics of scattering media having equivalent spectral extinction do obey. The algorithm of solving the inverse problem, based on minimization of the discrepancy between the measured scattering phase function and that calculated from the microstructure, retrieved from the inversion of the light extinction coefficient, is verified and tested in numerical experiments. The estimates of the error of determination of the real and imaginary parts of the refractive index are calculated, which do not exceed 0.05 and 0.03, respectively.