The new widely used iterative method named forward-backwardmethod is given to calculate finite beam scattering from the conducting time-varying sea surface with Pierson-Moskowitz spectrum by solving the electricfield integral equation. Numerical results for the angular distributions of thebackscattering cross sections with different surface length, sample interval anddifferent velocity of the wind are discussed, respectively. Emphasis is put onwith the electromagnetic backscattering at low grazing angle incidence, it isshown that the backscattering cross section is proportional to the nearly fourthpower of the grazing angle for the plane and beam incidence.