Precipitation extremes have become more frequent under global warming,which attract widely attention of scholars at home and abroad,and the appropriate threshold is the first step of studying precipitation extremes.In this paper,we use data sets of daily precipitation recorded in 499 meteorological stations,through the comparison of DFA method,percentile method and Pearson-III distribution to define the proper threshold for each station and each region.Results show that:Thresholds calculated by DFA are much higher than the percentile method and the values are around the return period of two years.Thresholds decreasing from southeastern coastal areas to northwestern inlands and thresholds are the highest in Sichuan Basin,middle and lower Yangtze River and southern part of South China.Our suggest thresholds in four major regions-South China,North China,Qinghai-Tibet Region and Northwest China are 80mm,50mm,25mm and 15 ~25mm.