AIM: To explore the mechanism of PX-12 induced apoptosis of hepatocellular carcinoma cells. METHODS: Human hepatoma cell line Huh7 was selected as the main research object. After the cells were treated with thioredoxin inhibitor PX-12, the cell viability was detected by CCK8 method, the cell migration ability was detected by cell scratch test, the cell proliferation ability was detected by cell proliferation kit, the levels of intracellular reactive oxygen species and apoptosis were detected by flow cytometry, and the expression of apoptosis-related proteins were detected by Western blot. RESULTS: Compared with the control group, the cell viability, migration ability and proliferation ability of PX-12 treatment group were significantly decreased (P<0.05), and the level of intracellular reactive oxygen species was increased (P<0.05) in a concentration-dependent manner. Apoptosis inhibitor Z-VAD-FMK and antioxidant NAC could restore the cell viability, and NAC could reduce the accumulation of intracellular reactive oxygen species induced by PX-12 and restore the apoptosis induced by PX-12 (P<0.05). CONCLUSION: PX-12 induces apoptosis of hepatocellular carcinoma cells through oxidative stress.