The concept and the measuring theory of BRDF (bi-directional reflectance distribution function) were discussed. A set of system based on personal computer for BRDF measurement was developed, whose laser wavelengths cover 0.6328 μm, 1.34 μm, 3.39 μm and 10.6 μm from visible to infrared. The experimental results of the hemispherical reflectance measurements on silicon carbide paper at normal incidence show better Lambertian diffusion.