Abstract: In the view of radiation transfer theory, the cloud optical parameters: βe, ωo and g are calculated under the different cloud droplet size distributions, and their influences on cloud reflectivity, transmissivity and absorptivity are investigated. And, the effects of inhomogeneities of cloud droplet size distribution and cloud liquid water content in the vertical direction on assemble cloud radiative properties, radiative flux density and heating rate in the cloud are also estimated.