OBJECTIVE To study the effect of extract of Radix Tetrastigma hemsleyani on the proliferation and apoptosis of human lung carcinoma H1299 cells, and to explore its mechanisms. METHODS H1299 cells were treated with the extract of Radix Tetrastigma hemsleyani in different concentrations at different time points. Its inhibition on H1299 cell proliferation was detected by Cell Counting Kit-8 (CCK-8) assay. The morphology of the H1299 cell was observed by inverted microscope. Changes of apoptosis were observed by Hoechst33258 methods. The apoptosis rate was detected by flow cytometry. Expression changes of apoptosis-related proteins pro-caspase-3, pro-caspase-9, cle-caspase-3, cle-caspase-9, and poly-ADP-ribose polymerase (PARP) were detected by Western blot. RESULTS Compared with the control group, the inhibition rate of H1299 cells increased after acted by 0.5, 1, 5, and 10 mg/mL extract of Radix Tetrastigma hemsleyani (P < 0.05, P < 0.01). The longer the acting time, the higher the inhibition rate (P < 0.01). Under inverted microscope, typical morphological changes could be seen and the number of H1299 cells was reduced. Under fluorescence microscope, dark stained nucleus and formed apoptotic body could be observed. Results of flow cytometry showed that the apoptosis rate was obviously dose-effect correlated with the concentration of extract of Radix Tetrastigma hemsleyani. Results of Western blot indicated that compared with the control. group, the protein expression of pro-caspase-3, pro-caspase-9, and PARP were down-regulated and that of cle-caspase-3, cle-caspase-9, and cle-PARP were up-regulated by 5 and 10 mg/mL extract of Radix Tetrastigma hemsleyani (P < 0.05). CONCLUSIONS Extract of Radix Tetrastigma hemsleyani had obvious effect in inhibiting the proliferation and inducing apoptosis of human lung carcinoma H1299 cells, which might be achieved by activating the expression of caspase protein.