Based on the NCEP/NCAR wind field reanalysis data from the United States and the measured wind data from radiosonde stations, ground weather stations and mountainous wind observation towers in Yunnan, the characteristics of the atmospheric wind field in Yunnan are analyzed. The results show that the wind field in the middle and lower troposphere of Yunnan is dominated by westerly air in ordinary year, and the wind direction is stable, especially the southwest wind, and the variation of upper wind fields in winter, spring, summer and autumn is obvious. The prevailing upper wind direction at Tengchong and Simao radiosonde station is mainly west wind. In addition to the influence of northeast and southeast Yunnan and local topography, southwest wind prevails in most areas near the surface throughout the year. The prevailing wind direction in mountainous areas is mainly southwest. The average annual wind speed near the surface in Yunnan is 1.9m/s, which is larger in the north than in the south, and larger in the east than in the west. The wind speed is large in winter and spring, and the wind speed is small in summer and autumn, and the diurnal variation of wind speed is significant. The atmospheric boundary layer temperature inversion phenomenon exists in Kunming area, which is prominent in winter, weak in summer, high frequency occurs in autumn, winter ,spring and low frequency occurs in summer.Air pollution in Yunnan is distributed in wet and dry seasons,the main pollution period is from January to May. In winter and spring, there are two pollution transport channels in southwest and northeast.