Both the theory and experiment for the passive remote sensing of snow with microwave radiometers have been studied. We account for volume scattering effects of snow by incorporating Mie scattering theory into a radiative transfer model. The theory is applied to the interpretation of experimental data obtained from various snow measurements. The spectral and angular dependences of the brightness temperatures are illustrated ans show good agreements between the theory and experiment. The brightness temperatures as a function of snow depths are also interpreted and discussed. It is observed that as the snow depth increases, the brightness temperature increases when the subsurface is an aluminum plate due to the fact that the plate is cold and snow absorption induces brightening effect and the brightness temperature decreases when the subsurface is soil due to the fact that snow scattering induces darkening effects.