The spatial domain building method is used to generate rough soil surface with Alphastable distributions，the characteristic of electromagnetic scattering from rough soil surface in the condition that the tapered wave incidence by using method of moment. The varying relationship of scattering coefficient with scattering angle is numerical calculated, the influence of the stability coefficient, normalized scale parameter, crosscorrelation length, the incident wave frequency, and moisture of soil on the scattering coefficient is analyzed. The results show that the influence of the stability coefficient, normalized scale parameter, crosscorrelation length, the incident wave frequency, and moisture of soil on the scattering coefficient is obvious, and the different laws are obeyed.