The cloudiness over Yunnan area,which is located from 99-104°E and 23. 5-28. 5°N,was calculated by the Infrared Threshold method with the corrected multi-channel AVHRR data of NOAA-10, 11 in one year period (from May in 1989 to APril in 1990), and the statistical cloudiness distribution was also analysed. The synoptic system and cloud system influence this area mainly, moreover, some cloud climatological characteristics were found. The results were examined by comparing with conventional observational results. Cloudiness over 21 points were obtained,which could be provided Yunnan Astronomical Observatory.