From middle January to the beginning of February in 2008, the extremely icy rain and snow weather processes occurred in most areas of South China. Using the NOA A18 OLR data in National Satellite Meteorological Center, the extremely icy ra in and snow processes in the beginning of 2008 is tried to analyzed. The results show that the relationship between fiveday [JP2]OLR anomaly and fiveday pre cipitating amount is as follows: Y=A+B×OLR The correlation coeffic ient of the equation is 0.60525 in South China. The standard deviation of monthly OLR in China during 1989-2008 is higher than the standard deviation during 1989 -2000, which indicates the increasing of the extremely weather events in recent years; The location and intensity of the abnormal precipitation processes are we ll reflected by the OLR isogram and OLR anomaly isogram. On daily OLR isogram, t he lower the OLR is, the higher the cloud is, and the more intense precipitation is. On five and tenday average OLR isogram, the lower the OLR value is, the l onger the sustained time of clouds is. On five and tenday anomalous OLR isogra m, the lower the anomaly is, the stronger the precipitation processes are and th e longer the sustained time of the processes are. Finally it is noted that the p recipitation process produced by stratus clouds with inverse temperature is not well reflected by OLR data. This is because that the temperature of the stratus cloud is nearly the same as surface, OLR value of the clouds is high and anomaly of OLR is not negative. It is a disadvantage of application of OLR to analyzing disastrous precipitation weather process.