This research is aimed to isolate the active constituents of Ginseng stems and leaves and study their anti-cancer activities. Preparative TLC, spectral data analysis and MTT assay are used to isolate constituents and study anti-cancer activities. Six compounds are isolated from Ginseng stems and leaves, namely 20(S)-ginsenoside Rh1, ginsenoside F3, daucosterol, β-sitosterol, ginsenoside Rd2 and 20(R)-ginsenoside Rg2. Inhibitory effect of ginsenoside Rg2 on growth of NCI-H1650 cells is detected by MTT and Annexin-V-PI double staining assays. The results show that different concentrations of ginsenoside Rg2 test solutions can inhibit the growth of NCIH1650 cells to varying degrees, and the effect presents evident dose-response and time-effect relationships, that is, the longer the action time, the stronger the inhibitory effect. It can be concluded that the active constituents in Ginseng stems and leaves have significant anti-cancer activity.