We investigate polarization and attenuation characteristics of X,C and S bands of dual-polarization radars with monodisperse raindrops of equivalent spherical diameter, different rainfall intensities and different maximum raindrops diameters using by T-matrix scattering simulation. Attenuation correction relation of radar reflectivity and differential reflectivity is established for the three bands of dual-polarization radars in medium of rain. Finally, accuracy of the scattering simulation results is verified by measured raindrop spectrum data and measured reflectivity data of X-band dual-polarization radar.