Abstract: Using anatomy, color tests (CT)and thin layer chromatography (TLC), morphological and chemical studies on Thamnolia vermicularis (Sw.)Ach. ex Schaer. and Thamnolia subuliformis (Ehrh.)W. L. Culb. were carried out, and variant under these two species have also been studied. Very few differences were observed between the original species and variant, though intermediate forms were found, and chemical compounds were the same, thus, T.vermicularis f.qomolangmana and T.subuliformis f.minor were synonymized. Taxonomic characteristics of Thamnolia are clarified, species boundaries are newly defined, and distribution ranges of the genus Thamnolia in China are discussed in this paper.