A review on recent definitions of the onset and end dates of the First Rainy Season (FRS) in South China was made in this paper. To make an objective and significant definition, suggestions on the usage of the data, the selection of the appropriate region and the representative stations in South China, the pe riod of the rainy season, the threshold of each parameter quantity, such as prec ipitation, wind field and so on, and their synthesis are reasonably discussed un der the reference measures in defining Meiyu and the summer monsoon precipitatio n which are all related with the judgment on date definition.