Abstract: According to the internationally recognized principle of authenticity in the renovation of ancient buildings, it has become a globally accepted ideal that the timber materials used in the maintenance of ancient wooden constructions should be of the same species and quality as the original ones and be processed in the same method. This paper discusses the special nature of the maintenance material used in the ancient wooden buildings of the world heritage, then explores the functions of the urban forest which has been developing rapidly in China in recent years, and puts forward the following proposals: we should get knowledge of the material requirements of ancient wooden buildings after surveying them, then make urban forest play a new function of nurturing the special maintenance material for ancient wooden buildings by adjusting the urban green space planning, and finally achieve sustainable preservation and inheritance of the important cultural heritage of our country in the long-term strategically.