Taxonomic studies in morphology anatomy, cytology, palynology were conducted to understand the interspecific relationships among 4 species in the genus Codonopsis in Korea. The vegetation in natural habitat for Codonopsis was also investigated. Morphological differences were observed among 4 species in leaf size, root shape, presence or absence of seed wing and hair, number of hair and floral color. The vegetation in 3 species, except for C. minima, was included in Q. mongolica association which is followed by the subassociation of Syunrus deltoides, Vitis flexuosa and Angelica dahurica. C. minima coexisted together with Taxus cuspidata, Rhododendron schippenbachill, Solidago virgaaurea var. leiocarpa, Spodiopogon sibiricus, Juniperus chinensis var. sargentii. The chromosome number was 2n=16 for all 4 species. The anatomical characters of root, stem, petiole, midvein of leaf were also described for the species. Especially xylem numbers and shape of petiole were different among them. The size of adaxial epidermal cells was larger than that of abaxial epidermal cells, and the stomatal apparatus was observed only in abaxial surface. Pollen shape of C. minima was monad and diameter of equatiorial plane of pollen grain was 30.0-36.1-46.5㎛ and polar axis was 27.0-39.-40.0㎛. Morphology of aperture was 8-10 colpate in C. minima, and the surface sculpturing was echinate in reticulate. According to the above observations in morphology, anatomy, cytology, palynology, the significant differences were found 4 species and C. minima was considered to be an independent species rather than a variety of C. ussuriensis.