Abstract: Modeling of scattering has become a research hotspot in the area of room acoustics computer simulation. Current methods mainly consider the surface property like structure and roughness,and cannot obtain accurate results at low frequency bands.The neglect of edge diffraction is one of the most important reasons.In this paper,an approach that combines modeling surface scattering and scattering caused by edge diffraction,has been presented.The predicted and measured acoustic parameters have been compared in order to validate the algorithm.The rules for determining surface scattering coefficients have also been recommended.