An anti-fungal derivative of rosin was synthesized. First, rosin was modified by acrylic acid and the modified rosin was esterified by epoxy chloropropane with the mole ratio of 1:3 for 3.5h at 90°C. The intermediate was bis 3-rosin acyloxy-2- hydroxypropyl chlorine and the degree of esterification was 98.81%. Then, bisN-(3-rosin acyloxy-2-hydroxyl) propyl-N,N dimethylamine was made from the intermediate under the following conditions: the intermediate and dimethylamine mole ratio of 1:2, reaction temperature of 80°C and reaction time of 2.5h. The chemical structure of the product was identified by Fourier transform infrared spectroscopy (FTIR). The anti-fungal activity of the product was determined by paper-disc method with wood decay fungi such as Trametes versicolor, Gloeophyllum trabeum and wood stain fungi such as Aspergillus niger and Paecilomyces variot Bainier. The anti-fungal experiment results signified that bisN-(3-rosin acyloxy-2-hydroxyl) propyl-N, N dimethylamine is active vs. these fungi, but less effective with Aspergillus niger. Since it is produced easily from rosin, which is renewable and not expensive, this product has a promising future as a potential wood preservative.