41.37％。A novel biodiesel was prepared by a twostep technology from the seed oil of Acer truncatum Bunge, a woody oil-bearing plant. Technological conditions of the esterification were investigated, and the composition of the product was analyzed by gas chromatography (GC). The technological parameters to reduce the acidity of the oil in the first step were as follows: the ratio of methanol to the oil was 6, amount of concentrated sulfuric acid as catalyst 0.6%, reaction temperature 50℃, and reaction time 90?min. In the second step however, the ratio of methanol to oil was 6, the amount of potassium hydroxide as catalyst 0.9%, reaction temperature 60℃, and reaction time 50?min. The conversion rate of seed oil of Acer truncatum was over 99%. The results of GC analysis showed that in biodiesel obtaining, the methyl esters of fatty acid with 18～20 carbon chains accounted for 91.54%, including 37.03% of methyl oleate, 41.37% of methyl linoleate. 