Inordertoimprovetheaccuracyoftherainfallmeasurement,aradar-radiometersystemhasbeendevel-oped.ItcouldbeusedtomeasurethedistributionoftherainfallintensityaLldthevariationofarearainfall.Infieldexperiment,theaccuracyoftherainfallmeasurementwasimporved.Inthispaper,theerrorofrainfallmeasurementbyradarwillbeevaluatedandthemethodstoimprovetheaccuracyoftherainfallmeasurementwillbediscussed.