It is necessary to study cloud parameter retrievals from cloud radiance measurements in order to obtain cloud-top height and temperature,cloud emissivity and thi-ckness, and perhaps cloud water content etc.This paper presents the preliminary results of the numerical test for retrieving two-level cloud height from a radiance ra- tioing method using NOAA satellite radiance measurements in the 15μm carbondioxide hand and 5,5μm oxygen band .(i.e. infrared and microwave channels). The comparison between the calculated and ground-thuth data shows that two-level cloud height can be obtained using a proper combination of two sets of channel measurements, but if middle and low level clouds Simultaneously occur these cloud heights can not be classified.