By modifying five-parameter semiempirical model of bidirectional reflectance distribution function (BRDF) and absorbing the advantages of other models, a six-parameter model of BRDF is proposed. The model, with simpler expression and better fitting effect, satisfies both reciprocity and energy conservation properties of BRDF, which enables the model to be practical. Simulated annealing algorithm is carried out on the statistical modeling of the BRDF of different samples, the corresponding model parameter values and deviation are obtained, the results verify the correctness of the model. According to the samples with weak scattering, which is especially suitable for this model, the diffuse component of the model has better fitting effect than that of the five-parameter model, and its total accuracy is slightly higher than that of the five-parameter model. Finally, to show the BRDF of the target samples visually, three-dimensional BRDF maps at differently incident angles are given.