The excavation and protection of ancient wood has become a significant research field in modern archaeology research. Using the Hai Menkou site as an example, fluorescence and polarization microscopy were used to analyze wood anatomy, to evaluate the level of decay in ancient wood, as well as the feasibility of reinforcement methods. The decay of ancient conifer wood could initially be divided into four levels. In comparison with natural resins, a phenolic resin was more effective for reinforcing and supporting the cell wall skeleton.