The spatial reflected characteristic and spectral characteristic from optical material surfaces were effectively described by the BRDF (Bi-directional Reflectance Distribution Function). The several measuring methods of the BRDF were analysed. A experimental table for the BRDF measuring was developed. With He-Ne laser and YVO4 solid laser, the measurements on 1500 CCR/RC.S.G silicon carbide waterproof abrasive paper were made within the -15°-65° of reflectance zenith angle. Finally, some difficulties in measuring BRDF precisely were mentioned.