In Jan 2011, a severe low-temperature freezing rain and snow storm that lasted 32 days hit Guizhou．It was the second largest freezing rain and snow storm since 2008．The episode was characterized by its wide spatial distribution, long duration, and three prominent intervals between strong cold air invasion and snow．In this study, we use the National Centers for Environmental Prediction(NCEP)reanalysis grid data with 1.0°×1.0° and 2.5°×2.5° resolution as well as Meteorological Information Comprehensive Analysis And Process System(MICAPS)observational data to analyze the phenomenon and its causes．From the analysis of the data we infer the following. 1) The synoptic feature had a dipole-type distribution in the middle-high latitudes of the Northern Hemisphere, and the polar vortex extended toward the eastern hemisphere in Jan 2011. The geopotential height anomalies over the Eurasian continent were of the "higher in the north and lower in the south" type．The blocking high pressure (BHP) was steady over the Eurasian continent．There are two times strong,stable,and long-lasting blocking circulations．2) The trough (disturbance) in the south branch (TSB) of the subtropical frontal zone was very active．The water vapor transport was disrupted four times during Dec 31 to Jan 2, Jan 9 to Jan 11, Jan 17 to 20, and Jan 27 to Jan 29. 3) The low-level shear at 25°N led to wind convergence,which provided favorable weather conditions for freezing rain and snow, and the stable and long-lasting quasi-stationary front strongly contributed to the rain and snow storm．4) The synoptic characteristics including the temperature field,frontal structure,and wind fields were different for the strong freezing rain,ice pellets, and snow storm．For the strong freezing rain,the height of the inversion layer was the lowest,the gradient was the largest,and the thickness was the thinnest and had a thick warm layer in the inversion field．The clouds stretched below 600 hPa, their upward motion was low, and they had warm-cloud characteristics. When the precipitation turned to ice droplets,the frontal inversion was lower with bigger inversion gradient and lesser thickness as well as a shallow warm layer．The clouds stretched into high altitudes,their upward motion remained low,and they had warm-cloud features. When the snow storm started,the height of the inversion layer was the highest, its gradient was minimum, its thickness was high, and there was not a warm layer in the inversion region. The clouds stretched above 500 hPa,their upward motion was the highest, and they had cold-cloud features．