Abstract: Expressions for the side-scattering cross-section and back-scattering cross-section of a small spheroid particle are given and then using the parameters in the bistatic weather radar system expresses the relevant parameters in this expressions.to defining the side-scattering capability of the small spheroid particle,the equations of side-scattering capability are derived for the cases in which the polarization of the transmitted radar wave is horizontal and vertical respectively.The side-scattcrmg capability distribution maps at the different altitudes can be obtained from the simulative calculation,and by analysis of these maps,we can conclude some referenced results.The main results include that (1)If the active radar emits horizontal polarization waves,the side-scattering capability decreases gradually to a minimum,and then increases gradually, with the increasing distance between the particle projection and the baseline at lower altitude.This characteristic exists at the extensions of the baseline on both sides, as well.As the altitude increases, the feature on the side-scattering capability is similar to that at lower altitude.But the capability has a slight strengthening around the passive radar.(2) If the active radar emits vertical polarization waves, the side-scattering capability of the whole lower altitude plane is always at a maximum besides the positions of two radarn.As the altitude increases, weaker scattering areas appear around the active radar and the passive radar, and the size of the areas is increasing with the altitude.