Abstract: Samples were collected from Styrax tonkinensis plants with different ages for analyzing some important chemical components. The total balsam acid and total triterpenes from different organs of S.tonkinensis were extracted and the content of crude protein, amino acids, and fiber from the leaves of S.tonkinensis were also determined. Distribution of each substance was studied, and significance of difference was tested. Results showed that: the total balsam acid and total triterpenes were the highest in leaves, followed by roots, the branches and trunks were lowest. With the increasing of tree age, the content of total balsam acid in leaf, root and shoot tented to increased first and then decline and finally increased. The content of total balsam acid in the stem decreased first, then increased and finally decreased. The content of total triterpenes in all organs showed a trend of decreasing first and then increasing and finally decreasing. The results of variance analysis showed that the difference of total balsam acid and total triterpenes contents of different organs in S.tonkinensis with different ages reached significant level. The average content of crude protein in the leaves was 7.08%, the average fiber content was 15.86%, and the average content of amino acid was 2.15%. The differences between crude protein content and amino acid content in leaves were not significant among different ages. The fiber content decreased with the increasing of leaf age, and the difference of fiber contents among leaves with different age were significantly different.