To reinforce ancient Pinus kesiya wood excavated from the Haimenkou site at Tianchuan, oxalic acid was used to for de-colorization, methanol for dehydration and rosin and shellac in methanol for enhancement. The whole enhancement process includes penetration and drying, and protection by experimental reinforcement. After reinforcement, the surface of the sample had a light color that preserved the original wood color, grain and texture. The density of the treated wood is 0.437 g/cm3, close to its modem counterpart. The parallel-to-grain compressive strength increased by 24.6% after reinforcement. Shrinkage rate, when the wood when completely dried, was: longitudinal direction, 2.2%; radial 3.5%; tangential, 7.7%. All shrinkage rates are within the normal rates seen when wood is dried. Scanning electron microscope (SEM) study showed that the natural resin stayed on the surface of the cell walls, providing great support for them. After reinforcement, the cell walls of the treated wood were smooth, dense and had clear outlines. There was good interface bonding between the cell walls, and the cell cavity was relatively smooth. This research shows that this reinforcement method can effectively decrease the hygroscopic properties of waterlogged wooden relics and improve their physico-chemical properties. When necessary, methanol or ethanol can be used to dissolve the rosin and shellac used, which means the treatment is reversible, allowing for the possibility for other, future treatment.