Based on the Mie theory，the light scattering properties in the visible regions of clouds consisting of pure water, pure ice spheres and concentric water_ice spheres are computed respectively. The reflection function and plane albedo, transmissivity, absorptivity of the three types of clouds are evaluated with the adding_doubling method by solving the radiative transfer equation. The numerical results show that the reflection function and plane albedo of ice clouds and ice_water clouds are slightly less than those of water clouds at most scattering angles, when the transmissivity is larger. A detailed theoretical analysis of the numerical results is presented, which explains the phenomenon of cloud absorption anomaly.