Abstract: The present application of rosin in wood preservation includes reducing moisture absorption of wood, improving water-based wood preservatives fixation, and preparing active rosin derivatives to wood-decay fungi. Wood-decay resitance can be improved by high concentration rosin emulsion treatment. Rosin emulsion treatment at even a low concentration could well fix leachable copper salts in wood. Rosin amine and quaternary ammonium salt derivatives could protect wood from fungal attack. Effects of imidazoline and other bioactive derivatives need more tests.