Abstract: baking the observed valid rain data in the airborne dual-frequency rain radar filed campaign on 2010 October 11 the drop size parameters is estimated by using the ratio of Ku band rain attenuation coefficient and effective radar reflectivity factor.Based on it,the effective radar reflectivity factor of Ka band is computed simulativcly and compared with the effective radar reflectivity factor detected on the airborne Ka band after attenuation correction.As a result, the simulated and observed Ka band radar reflectivity factor profile is almost coicident with each other and the correlation coefficient is above 0.95.What's more,the detected object is the same for the dual-frequency radar and the difference of measured radar reflectivity factor between Ka and Ku is caused by the difference of radar frequency, suggesting a good beams match situation.In addition,the estimated drop size parameters by single frequency relied on the precision of attenuation correction.Fortunately, the rain detected by the airborne radar is weak, and the attenuation correction of Ku band is reasonable and the drop size parameters are reliable.But,it is noticed that the drop size parameters estimation with a high precision still needs the dual-frequency rain retrieval method.