To study the relative relationship among the three species of Tripterygium genus by measuring the contents of 5 terpenoid compositions in plant leaves of Tripterygium genus and comparing the differences.Methods:HPLC was used to measure the 5 composition contents including Triptolide,Triptonide,Neotriptophenolide,Triptophenolide and Tripterine in 28 batches of plant leaves of Triptergium genus.ANOVA and cluster analysis were also performed to verify the results.Results:There were significant differences among the contents of Triptolide,Triptophenolide and Tripterine in the plant leaves of Triptergium genus (P<0.05); There was no significant difference between Triptonide and Neotriptophenolide.Hierarchical clustering was used to divide the 28 batches of plants of Triptergium genus into 4 kinds:I:Tripterygium regelii Sprague et Takeda and Tripterygium hypoglaucum; II:Tripterygium; III:Tripterygium; IV:Tripterygium and Tripterygium hypoglaucum.Conclusion:The differences of some contents of terpenoid compositions in plant leaves of Tripterygium genus were significant.The relative relationship of Tripterygium regelii Sprague et Takeda and Tripterygium was distant; Tripterygium hypoglaucum was between the two,which had no significant difference.