Abstract: The integration method for the solution of Maxwell equations with Born approximation is less utilized in the aero-optic numerical simulation because of its difficulty in the discrete calculation. Combined with the generalized CV-FFT(GCV-FFT)algorithm, the result has great accuracy in the numerical computation for the Rayleigh-Sommerfeld diffraction in free space. With some modification to the Green function and sampling coefficient, the integration method can be used in the numerical simulation of aero-optics. Propagation through a supersonic boundary layer shows that the effect of aero-optics (beam break, beam shift, etc.)can be well simulated by the integration method, combined with the generalized CV-FFT algorithm. The current method can be used to give a quantitative assessment of the other methods as well as being amenable to the addition of more physics.