Abstract: Based on the three basic requirements which should be met by a satellite-borne rain-measuring radar, researches on the combination of the soundest wave bands for FY3 a satellite borne rain-measuring radar have be made. The profiles of hydrometers and gases output by the high precision three-dimensional (3D) Goddard cumulus ensemble (GCE) model are used as the input of the Quickbeam radar simulation software. The detection nature for the five frequencies of 5, 10, 14, 35 and 94 GHz is discussed. To obtain a sufficient dynamic range in the near surface layer, it is necessary to select a lower frequency. Under the restrictions of the existing antenna hardware and the current technology level, 5 and 10 GHz are unpractical to be selected as the frequencies of the satellite-borne radar. The contrast analyses of the measured radar reflectivity factor and the effective reflectivity factor in three different typhoon areas show that there is an increasing attenuation with increasing high frequency. So, 94 GHz can t be used to detect rain. However, a high frequency has a better sensitivity to light rain and can make up the sensitivity deficiency of low frequency; so, a high frequency can be employed to detect light rain. Finally, according to the frequency allocations determined by the International Frequency Registration Board, the Ka and Ku bands should be chosen and 13.40-14.00 GHz in the Ku band and 35.50-35.60 GHz in the Ka band should be the soundest wave bands combination. The Ku band is valid for detecting heavy rain while the Ka band is valid for detecting light rain. The bands of Ku and Ka can be connected to improve the precision of precipitation retrieval.