Abstract: This paper deals with the correlation between phylogeny, chemical constituents and pharmaceutical aspects of plants based on our own works related to its practical applications. 1. Application in the search of domestic resources for the imported drugs: A series of imported drugs have been successfully replaced by the domestic sources of closely allied plants as supported by the laboratory and even clinical investigations. Several plants belonging to the genus Artemisia Sect. Seriphidium fere found to be rich in santonin and are currently used as the raw materials for its commercial production. 2. Application in exploring new sources of some important medicinal herbs: The total tanshinone and cryptotanshinone, isolated from Salvia multiorrhiza, have been demonstrated to be antimicrobial active substances, thus 14 species of Salvia were examined, as the result it has been shown that S. przewalskii and several other Salvia plants with red-coloured roots had a much superior activity. Eight species of Schizandra have been investigated for their possible occurence of the active principles (Ⅲ-Ⅵ etc.) along with their SGPT-lowering observations, while all of them exhibited the pharmacological effect except S. micrantha. Our study has proved high incidence of distribution of diosgenin in genus Dioscorea Sect. Stenophora. 3. Application in drug control and evaluation: While the Chinese traditional drug "Mudanpi" and "Shaoyao" are both derived from the genus Paeonia, with the former mainly from Sect. Moutan and the latter from Sect. Paeonia. their chemical criteria can be distinctly established. Preliminary investigation has been done on another wellknown Chinese traditional drug "Rhubarb", it is now evident that all the officinal Rhubarbs were that obtained from the Sect. Palmata of the genus Rheum, while some of the inferior Rhubarbs were that chiefly derived from the Sect. Rhapontica. Judged from the total fiavonoid contents of 6 species of Chinese Pueraria, it has been revealed that the traditionally used P. lobata still should be ranked as the best qualified one among them.