Abstract: Aiming at the limitation of the traditional tropical rainfall measuring mission (TRMM)Radar, we focus on the next generation precipitation radar system including the Ka-band measurement. In this paper, the scattering characteristics from complex precipitation particles in the K or Ka-band are analyzed by using the sparse-matrix/canonical grid (SMCG) method. We analyze the electromagnetic scattering characteristics of uniformly and randomly distributed rainfall particles model in the Ka-band. Finally, we give the wide-band scattering properties of rainfall particles with arbitrary shape randomly distributed in a certain region. Numerical results are given to supply theory foundation for the development of the next generation precipitation radar.