The radar and automatic precipitation station data of 5 to 7 June 2008 from the Guangdong provincial CINRAD network are used, an analysis is carried out of the observation differences of the radar networking system at 3 km over Guangdong Province, and it is discovered that observed values of Guangzhou radar, compared to nearby radar, are generally 1 to 3 dBz higher, and those of Meizhou radar are 1 to 2 dBz lower. With the Z〖CD*2〗R relationship and the optimum interpolation calibrated method, 6minute and 1hour quantitative rainfall estimations are conducted, and a verification is made using the basin average rainfall deviations and the rootmeansquare errors on the estimation effect. It is concluded: in 6minute precipitation estimation, two methods would underestimate precipitation, and the bigger the precipitation, the better the estimation effect is; in 1 hour precipitation estimation, the estimations of the two methods are generally higher, and the results of the radarraingauge estimation method is best, in which progressive accumulation and then calibration are performed; the shorttime precipitation estimation can reflect well the variation in precipitation processes, while the longterm precipitation estimations can estimate the amount of precipitation more accurately.