The method for reconstructing the disperse medium characteristics by means of linear functions of measured parameters in application to studies of the atmospheric aerosol is proposed. The optimization problem with restrictions in the form of the system of linear equations is formulated to find the coefficients of linear regression. The optimization criterion and additional a priori information are chosen with respect to the peculiarities of formation and existence of real atmospheric aerosol related to its multifractional structure. Application of the method to data processing of multifrequency laser sounding of the atmosphere is considered. Some results of numerical calculations are presented.