The light scattering characteristics of spherical metal particles are analyzed by numerical calculation method based on the Mie theory. A numerical calculation method for intensity function and polarization of the parallel incident beam scattered by small spherical particles is presented. The 3D graph for the intensity function and polarization varying with the scattering angle and the scale parameter was obtained by Matlab software simulation. The results show that with the increasing of scale parameter the number of polarization peak increases and the distance between the polarization peaks decreases. The variation can be used as theoretical basis for the detection of metal particle size.