Abstract: The regressional equation to reflect the correlations among fertilization quantities of nitrogen(N), phosphorus(P) and potassium(K) fertilizer and the triptolide contents in the Tripterygium wilfordii leaves was designed with common quadratic regression rotation combination method. The results showed that the effect of the three major elements on the leaf triptolide content was ordered as N>P>K, indicating the effect of nitrogen fertilizer made the relatively greater contribution to the increment of triptolide content in the leaves. Taking triptolide content in the leaves to be more than 88.71mg/kg as the agronomic objective, the optimal fertilization combination obtained by computer simulation was: 66.3~86.4 kg/hm2 of urea, 93.9~119.1 kg/hm2 of calcium superphosphate and 124.0~164.1 kg/hm2 of potassium sulfate. The highest triptolide content in the leaf samples of T. wilfordii reached 90.462~110.541mg/kg, which was 4.2~5.1 times of the triptolide content of the control.