The main characteristics of the general atmospheric circulation in December 2020 are as follows. Polar vortex in the Northern Hemisphere had a dipole distribution, the circulation presented a three-wave pattern in middle-high latitudes. The atmospheric circulation presented a great meridionality in mid-latitudes in Eurasia. The East Asian trough behaved strongly and the southern branch trough was weaker in this month. The monthly mean precipitation over China was 5.8 mm, 45.3 % less than normal (10.5 mm). The national monthly average temperature was -3.9℃, 0.7℃ lower than the normal. Totally, there were two strong cold air processes, two precipitation processes and two large-scale fog-haze events in this month. During 27-31 December, most of China suffered from the cold surge characterized by a sharply drop in temperatures and extremely wide areas being impacted. The lowest temperature in many places exceeded the historical extreme values.