To study random rough surface scattering distribution characteristics and influence factors of distribution characteristics, linear filtering method is used to generate Gaussian random rough surface, and Monte Carlo numerical method based on Kirchhoff Approximation is deduced to calculate the scattering light intensity spatial distribution from one set random metal and one set dielectric rough surfaces illuminated by S and P polarized light. The three characteristics of the scattering light intensity distribution peak, the intensity distribution width and the position of peak are reviewed. Numerical calculation results show that significant differences between scattering characteristics of metal surfaces and the dielectric surfaces exist. The light scattering characteristics are jointly influenced by the slope distribution and reflectance of surface element. The random rough surface scattering light intensity distribution is affected by common influence of surface element slope distribution and surface element reflectivity of random surface, and good consistency between the common influence result and numerical calculation result.