Through analyzing the fields of height, temperature, precipitation, vorticity and other elements, the major features of the circulation pattern causing the freezing rainfall and abnormal low temperature weather, as well the process of the extreme snow and freezing event in January 2008 over Guizhou Province are discussed. The result shows that under the background of strong La Nina, the blocking high persisted in the east of the Ural Mountains, and the polar vortex was abnormally strong and farther eastern; the western Pacific subtropical high became stronger with active south branch trough, which were possibly the major causes of the disaster. The obvious features are that there existed a cold air layer of below 0 ℃ under 850 hPa, a warmer layer near the 700 hPa, and a colder ice layer above. There existed positive relative vorticity advection and a southwest lowlevel jet, which transported beneficial sufficient warmer and wetter air and sustained the steady flow of heat to the melting layer. The difference between upper and lower vorticity advection was favorable for the development of ascending motion, which provided conditions for the occurrence of the snow and freezing rainfall.