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Satellite provides good observational data for the weather and climate analysis of the Tibetan Plateau. Three kinds of cloud fraction data that comes from PATMOS-x/NOAA, CLARA-A2/NOAA and MODIS / Aqua were evaluated over Tibetan Plateau. Compared with ground observation, PATMOS-x had the highest correlation and the mean correlation was higher than 0.8. Three kinds of long term cloud fraction data showed similar spatial and temporal distribution pattern, namely that eastern Plateau has more cloud than western, northern Plateau has more cloud than southern and day time has more cloud than night. All three kinds of cloud data made mistake with snow along the ridge of mountain. In the daytime, CLARA-A2 had the highest monthly average cloud fraction. At night, the monthly average cloud fraction of Aqua/MODIS was more than that of PATMOS-x and CLARA-A2 except in summer. All three kinds of cloud fraction had similar annual mean value. CLARA-A2 had minimum cloud fraction in summer and maximum cloud fraction in winter. The linear regression and accumulate bias analysis showed that the annual mean cloud fraction of both PATMOS-x and CLARA-A2 displayed a decrease trend from 1982 to 2015. The trend of night time cloud fraction was more obvious than that of daytime. CLARA-A2 displayed obvious trend than PATMOS-x, especially at night.
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