Abstract:The main characteristics of the general atmospheric circulation in May 2017 are as follows. There was one polar vortex center in the Northern Hemisphere, stronger than usual. The 500 hPa geopotential height presented the distribution of a multi wave pattern in the high latitude of Northern Hemisphere. The strength of Western Pacific subtropical high was a little stronger than in normal years, and the south branch through was a little weaker. The monthly mean temperature was 17.1℃, 0.9℃ higher than normal, which ranks the fourth highest since 1961. The monthly mean precipitation amount was 59.4 mm, which is less than normal (69.5 mm) by 14.5%, whereas an extremely strong precipitation event that broke the historical records occurred in Guangzhou on 7 May. Five rainfall processes occurred in Southern China this month, and an extremely high temperature event happend in Northern China. Severe droughts occurred in the west part of Northeast and North China, and two dust weather events happened in the northern part of China.