The genus Tripterygium Hook. f. (Celastraceae) has siginificant medicinal value. This genus distributed from mainland China, across Korean Peninsula and to Japan. Great morphological plasticity of the species, insignificance of genetic differentiation among species with overlapped distribution range, and scarcity of comprehensive phylogeography studies lead to the controversiality in taxonomic treatment of species and difficulties in understanding evolutionary issues such as speciation and formation of the distribution pattern. In this study, we will intensively harvest the population sample from its distribution range. The objectives of our study focus on: 1) construction of phylogeny of this genus using genetic varations from both chloroplast and nuclearDNA markers; 2) detecting the genetic diversity of populations, genetic structure and phylogeographical pattern using DNA variations and microsatellite analysis; 3) estimation of the divergence time of taxa by calibrating the molecular clock using fossils, and evaluation of the impact of climate fluctuations, fragmentation of land bridge, geographic barriers on currrent phylogeographic distribution pattern of Tripterygium. We expect to provide a case study and accumulate data for investigating the origins of the East Asian flora and the relationships of the flora of China mainland, Japan, Korean peninsula, and Taiwan.