For big particles, the geometrical optics approximation model(GOM) with clear physics sense is considered to be a better method for calculating light scattering.The GOM is analyzed in this paper, and the scattering angle is a multi-function of the incidence angle, namely, a scattering angle is possible to correspond to multiple incidence angles.For a scattering angle with the multi-value problem, a method of traversal value based on MATLAB for solving the angle of incidence is presented.And the single-and t...