Stray light propagation in the baffle with honeycombed wall is divided into two levels, the scattering inside honeycomb structures and the transmission by the equivalent surface of inner wall. An anisotropic reflection model is established to predict the bidirectional reflectance distribution function (BRDF) data of the surface. By simulating the stray light propagation with the Monte-Carlo method, the suppression property of the baffle and the effects of coating reflectivity and geometric parameter of honeycomb are investigated. The results show that the baffle with honeycombed wall has a good performance of stray light suppression, and lower reflectivity of coating can enhance the performance.