Rhododendron Molle G. Don belongs to Ericaceae family. As a toxic traditional Chinese medicine, its roots, flowers, and fruit are often mixed and substituted arbitrarily to treat rheumatoid arthritis in clinic. To clarify the main chemical basis of each medicinal part, and provide sufficient scientific basis for clinical application, analysis using HPLC-ELSD of the roots, flowers, and fruit from R. molle was established, and characteristic chemical constituents of them were separated by tracking. The structures were determined by NMR methods. Finally, 16, 21, and 18 compounds were obtained from the roots, flowers, and fruit, respectively. Overall, 49 compounds were obtained, of which 25 were identified for the first time in R. molle. Meanwhile, among the obtained compounds, 12, 11, and 6 characteristic peaks were identified from the roots, flowers, and fruit, respectively. Thus, the basic chemical substances of the medicinal parts of R. molle were determined initially.