Abstract: In this paper, we achieve the efficient computing of electromagnetic scattering for Gaussian rough surface based on the stochastic integral equation method(SIEM). Compared with the traditional method to solve the electromagnetic scattering the Monte Carlo method, SIEM only computes the matrix elements and the unknown current units once by using the statistical surface-unit Green's function to couple the field and source, which is very efficient. The numerical results coincide with the Monte Carlo method very well and the computational efficiency is greatly improved.