Abstract:The following are the main characteristics of the general circulation of atmosphere in September 2010. The polar vortex center over the Northern Hemisphere is single. The circulation presents a four wave pattern in middle high latitudes. A negative anomaly with more than 120 gpm difference is found over the sea east of Iceland on 500 hPa geopotential height field. The intensity of the subtropical high over the Northwest Pacific is stronger than the corresponding period of normal years. The location for the west ridge spot is near 24°N, 100°E, which is more northerly and more west than normal years. The monthly mean temperature (17.1 ℃) is 1.1 ℃ higher than the same period of normal years and the national mean precipitation (85.1 mm) is 19.7 mm more than the same period of normal years. In this month, there were 3 obvious cold air processes and 7 precipitation processes, 4 tropical cyclones generated, which were named Malou, Meranti, Fanapi, and Malakas respectively, in which Meranti and Fanapi landed in China and resulted in heavy damages.