Abstract: Biochemical measurements were carried out with root, bark and leaf of normal growth(as the control)and infected Pinus armandii by aphid and mite.The comparsion between the infected tree and control was made in order to identify the diagnostical index for determining the vitality of Pinus armandii. The results showed that the sugar, phenoli compound in the tissues of infected trees were lower than that in normal trees.The peroxidase activity and polyphenoloxidase were higher in infected tree than that in control.By comparing the healthy plant with inhealthy one infected by aphid, the peroxidase enzymatic of root and stem tissues was larger than leaf tissues.