To analyze the chemical constituents of ethanol extract of Radix Astragali, and to study their inhibitory effect on HepG2 cell line proliferation. Column chromatography, thin-layer chromatography and preparative liquid chromatography were used to extract and isolate compounds, and NMR spectroscopy was used to analyze the structure of the compounds; MTT assay and flow cytometry were used to determine the anticancer effect of the ethanol extract of Radix Astragali. Four compounds were isolated from the ethyl acetate and n-butanol fractions of Radix Astragali ethanol extract, which were structurally identified as astragaloside, uridine, 7,2'-dihydroxy-3',4'- dimethoxyisoflavan- 7,2'-dioxo-β-D-glucoside and (3R)-8,2'-dihydroxy-7,4'- dimethoxyisoflavan. MTT assay results showed that HepG2 cell growth was inhibited to varying degrees in each experimental group, and the inhibitory effects exhibited apparent dose- and time-effect relationships, the longer the drug action, the stronger the inhibitory effect; flow cytometry found that 48 h after the action of different concentrations of Radix Astragali ethanol extracts on HepG2 cells, the apoptosis rate of HepG2 cells significantly increased. Within the experimental dose range, Radix Astragali ethanol extract has proliferation inhibitory effect on HepG2 cells.