Abstract: OBJECTIVE To screen the antitumor active fraction extracted from the roots of Actinidia eriantha Benth in vitro and determinate the total triterpenoid. METHODS The proliferation inhibition effects on A549 and HepG2 cells in vitro were tested by RTCA DP real-time cell analysis system and the content of triterpenoids in roots of Actinidia eriantha was detected by ultraviolet spectrophotometry.RESULTS The experiments showed the extracts from roots of Actinidia eriantha had a great inhibitory effect on A549 and HepG2 cells in vitro. The inhibitory effect of the petrol ether, ethyl acetate and ethanol extracts on A549 human tumor cells with IC₅₀ values of 2, 0.15, 3.8 mg·mL^-1, respectively. The inhibitory effect of the extracts on HepG2 human tumor cells with IC₅₀ values of 75, 7.6, 71 μg·mL^-1, respectively. It was found that the content of the total triterpenoids in the ethyl acetate extract of roots of Actinidia eriantha was 45%. CONCLUSION This study confirms that the ethyl acetate extract has significant anticancer effect in vitro and the total triterpenoids may be its antitumor active ingredient.