Abstract: Based on the stable isotope (D, 18O) in precipitation selected at Guangzhou from November 2007 to March 2008 and the meteorological data, the isotopic variations of precipitation at short-time scales was analyzed. On the daily time-scale, there is a significantly positive relation between the 18O and D in precipitation with the daily air temperature, and this could be correlated to the occurrence of the severe cold surge, ice-snow and frozen disasters in the south China at the beginning of 2008. We also find that there are mainly two kinds of the isotopic changing tendency during one single precipitation process. One kind is an obvious declining pattern during the continuance of the rainfall process, and another kind is a V pattern during the rainfall process, and it is quite similar with the variation of its d-excess. We concluded primarily that these different kinds of isotopic variation patterns were probably correlated to the water sources, frontal activities, evaporation, dephlegmation processes and etc.