The following are the main characteristics of the general circulation of atmosphere in April 2011. There is one single center of the Northern Hemisphere polar vortex and is located in the Western Hemisphere. There are three waves around the earth in middlehigh latitudes and is one wave in Asia area. The East Asia deep trough is stronger, the subtropical high is obviously weaker than climatological normals and the south branch trough is approaching the climatological normals. The monthly mean temperature averaged over China is 11.3℃ which is 1.0℃ higher than climatological normals and that in Northwest China is obviously higher. The monthly mean precipitation averaged over China is 21.4 mm which is 22.4 mm less than climatological normals. There are four cold air currents and four sanddust processes in April respectively. Some provinces and regions are hit by severe convective storms.