A new Rayleigh approximation for the scattering of electromagnetic wave by spherical sand with non-uniformly distributing charge is proposed, and some numerical simulation results on the differential scat? tering cross section (DSCS) and the scattering efficiency are discussed. The results show that, the DSCS pres? ents an obviously spatial distribution while the charge is non- uniformly distributing on particles, but it shows an isotropic scattering property while the charge uniformly distributes on the sand. In addition, for a given charge density, the scattering efficiency for the former is much smaller than the one when the charge uniformly distributes on sand, but in some charged angle the law becomes contrary to the former law. These results illus? trate that it is needed to consider the effect of the surface charge and its distribution form while using the mi? crowave radar to monitor the dust storms.