Models based on microfacet were used to describe spectropolarimetricBRDF (short for bidirectional reflectance distribution function) withexperimental data. And the spectropolarimetric BRDF values of targets weremeasured with the comparison to the standard whiteboard, which was considered asLambert and had a uniform reflectance rate up to 98% at arbitrary angle of view.And then the relationships between measured spectropolarimetric BRDF values andthe angles of view, as well as wavelengths which were in a range of 400-720 nmwere analyzed in details. The initial value needed to be input to the LMoptimization method was difficult to get and greatly impacted the results.Therefore, optimization approach which combines genetic algorithm and Levenberg-Marquardt (LM) was utilized aiming to retrieve parameters of nonlinear models,and the initial values were obtained using GA approach. Simulated experimentswere used to test the efficiency of the adopted optimization method. And thesimulated experiment ensures the optimization method to have a good performanceand be able to retrieve the parameters of nonlinear model efficiently. Thecorrectness of the models was validated by real outdoor sampled data. Theparameters of DoP model retrieved are the refraction index of measured targets.The refraction index of the same color painted target but with differentmaterials was also obtained. Conclusion has been drawn that the refraction indexfrom these two targets are very near and this slight difference could beunderstood by the difference in the conditions of paint targets’ surface, notthe material of the targets.BRDF； Microfacet model等学校博士学科点专项科研基金项目(20060699032), 航空科学基金项目(2007ZC53037)和西北工业大学英才计划基金项目资助