147 automatic weather stations (AWS) were deployed in 2006 over an area of about 100 km×100 km between Changchun and Siping in Jilin Province. We performed quality control (QC) of the hourly precipitation data from the densely distributed AWS rain gauges for April to October in 2007-2011. After four QC evaluations and a comparison with reflectivity data from C-band weather data in Changchun, data from six gauges were removed and questionable data from several sites were marked but kept for future use. Rain gauge data correlations were calculated after the QC. The results show that the averaged correlation coefficient (CC) is about 0.6 when the distance between gauges is less than 10 km and up to 0.7 or higher when the distance is less than 5 km. CC generally decreases to less than 0.4 when the distance exceeds 20 km. Furthermore, the spatial representativeness of measurements from a single rain gauge increases when the statistical time scale changes from minutes to months.