The bidirectional reflection distribution function (BRDF) of the machined surface morphology of optical elements was analyzed based on C-T model, a simulation model of the surface morphology was established for the precision cutting surface of optical components, the influence of incident light parameters and surface microstructure parameters on BRDF was simulated and analyzed by Matlab software. The results show that the peak value of BRDF function increases with the increase of incident Angle and incident wavelength under the same micromorphological parameters. When the parameters of the incident light are the same, the change of the parameters of the microscopic morphology will cause multiple scattering and shielding effects of the incident light on the surface, which will change the peak value of the BRDF function. With the increase of root mean square height, the scattering and shielding effects increase, and the peak value of BRDF function decreases. The peak value of the BRDF function increases with the increase of the contour width and decreases with the increase of the root mean square slope.