A measurement method of bidirectional reflectance distribution function (BRDF) on the cutting surface is proposed based on the coaxial optical microscopic imaging. The BRDF measurement values on sample surfaces with different roughnesses are obtained by using the laser confocal microscopy. The measurement results show that, the BRDF on the sample surface varies with the roughness and the micro-topography, and this measurement method can obtain the BRDF measurement value on different microfacets. The BRDF parameter model is built and the optimal model parameters are obtained when the measurement data are processed by the genetic algorithm. The error analysis between the model calculation results and the measurement results is carried out and the maximum relative mean square root error is 9.97%. The results show that the established BRDF model is feasible and can accurately describe the reflection characteristics on the cutting surfaces.