Abstract: The source of stray light of the laser gravitational wave telescope is mainly the reflected stray light generated by the thin beam incident on the mirror surface. When the laser light intensity of 1 W was incident, the stray light intensity needs to be suppressed to less than 10-10 W, otherwise the measurement accuracy of the main parameter optical path difference will be seriously affected. Aiming at the background of this application, the feasibility of Bidirectional Reflection Distribution Function(BRDF) parameters for mirror surface reflection characteristics reconstructed by stray light test data was considered when the thin beam incident on the mirror surface. In the traditional measurement of BRDF, four corners were required. The system was complex and inconvenient for real-time application. Based on the isotropic optical elements and the symmetry of mirror stray light model, considering the plane mirror, curved mirror and beam diffraction effect, measurement error and other factors, a method reconstructing the BRDF parameters by one-dimensional measurement the scattering of several points with the plane mirror rotation in the meridian plane was proposed, and the feasibility and measurement accuracy were verified by numerical methods.