Disclosed is a system for estimating a snow depth including: an optical disdrometer for acquiring information on diameters of snow particles and particle number concentration; a laser snow depth gauge for measuring the height of snow accumulated through a laser beam type sensor to provide an observed stop depth; an estimated snow depth equation calculator for determining an optimal index for the diameters of the snow particles provided by the optical disdrometer, substituting the optimal index for a snow depth calculation equation as a first mathematical equation to calculate a computed snow depth, obtaining correlation between the observed snow depth and the computed snow depth, and calculating a regression equation between the observed snow depth and the computed snow depth as an estimated snow depth equation; and a snow depth estimator for estimating the snow depth on the basis of the estimated snow depth equation, and the first mathematical equation.