Based on the NCEP, routine surface observation and sounding data, three cold waves occurred in 2008—2009 in Guangxi are comparatively analysed in respect to intensity, influence, vapor, dynamic and thermodynamic mechanism. The results show that the cold waves intensity is related to the later or sooner appearance of polar vertex which is off-center against East Asia and the inverted Ω flow pattern. The temperature decrease caused by the 500 hPa horizontal trough turning to longitudinal style was more intense than that caused by the horizontal trough moving southward style and the small trough moving eastward. The cold wave in December of 2008 belonged to the 500 hPa horizontal trough turning to longitudinal, sleeting appeared, but it turned clear quickly. The cold wave in January of 2008 belonged to the horizontal trough moving southward. After the cold wave there still were cold air supply to the south, so it led to long term low temperature and frost weather. The cold wave in February of 2009 belonged to the small trough moving eastward. Even through the temperature decrease wasnt stronger than the others, but the Indian-Myanmar trough developed, the water vapor supply was enough to sustain long term raining weather. The quasi-geostrophic Omega equation analysis showed that the upward vertical motion of the cold wave with sheeting in December of 2008 was caused by the positive differential vorticity advection between 500 hPa and 850 hPa. The upward vertical motion of the cold wave with raining in February of 2009 was caused by the 850hPa warm advection moving upward.