In terms of data on radiation and cloudiness from ERBE and ISCCP, outgoing longwave cloud-radiative forcing(LWCRF) and cloud greenhouse effect(CGE) are investigated on seasonal and annual bases over the Tibetan Plateau.Results show that a good power-law correlation exists between LWCRF and either total or high cloudiness. The LWCRF changes seasonally and has a geographical distribution similar to that of total cloudiness, its value being higher in spring and lower in winter or autumn.