The principal angle and ellipticity of the light beam reflected from the surface of porous silicon (PS) and the dependence on the angle-of-incidence of the reflected light intensity were measured for three wavelengths of the visible spectral region. The data obtained indicate the presence of a practically transparent layer on the PS surface. The layer refraction index and thickness as well as the optical constants of the PS substrate were determined. The regions with thicker layers are established as showing more intense photoluminescence.