Phytochemical investigations of the leaves of Astragalus membranaceus (Fisch.) Bge. have led to the isolation of 12 undescribed triterpenoid saponins named huangqiyenins M–X. The structures of the undescribed compounds were determined using NMR and HRESIMS data. The cytotoxicity of these compounds against the RKO and HT-29 colon cancer cell lines was evaluated. Among these compounds, huangqiyenin W exhibited the highest cytotoxic activity against RKO colon cancer cells, whereas huangqiyenin Q and W showed moderate cytotoxic activity against HT-29 colon cancer cells. The network pharmacology results indicated that STAT3, IL-2 and CXCR1 are the correlated targets of huangqiyenin W against colon cancer, with AGE–RAGE and Th17 cell differentiation as the key signaling pathways.