Abstract: In order to assess the safety grade of the ancient timber buildings by limited testing results,a gray-fuzzy analytical method of safety assessment of ancient timber buildings was proposed based on gray system theory and fuzzy mathematics. The classification principles of the members,sub-systems and appraisal systems of ancient timber buildings and their safety grades were studied and reviewed. The determination principles of the properties gray-fuzzy relation matrixes and the weight vectors were recommended. A typical ancient timber building for civil use was exemplified to apply the proposed method to assess its safety grade. It shows that gray-fuzzy analytical method is uncomplicated and practicable to assess the safety grade of ancient timber buildings. Compared with the traditional grade assessment method,the proposed method takes consideration of the diverse contribution of different members to building safety and the different contribution of a member's each property to its safety grade.