Objective To investigate the influence of Venenum Bufonis on proliferation and apoptosis in liver cancer cell HepG2 and relevant mechanisms. Methods Cell viability CCK-8 method was used to detect the influence of Venenum Bufonis on proliferation in liver cancer cells. Hochest 33258 staining technique was used to observe the influence of Venenum Bufonis on cellular karyotype and the apoptosis was detected by Annexin V-FITC/PI kit and flow cytometry. Rhodamine 123 staining method was used to detect the effect of Venenum Bufonis on mitochondrial membrane potential on flow cytometry. Cells were pretreated with apoptotic factor caspase8/9/3 specific inhibitors and the effect of Venenum Bufonis on cell viability was detected by CCK-8 method. Results Cell viability detection showed that Venenum Bufonis killed cells in an obvious concentration-and time-dependent manner. Confocal microscope observation found that Venenum Bufonis significantly caused nucleus shrivel, which resulted in forming apoptotic body. Treatment with 20 μg/mL Venenum Bufonis for 24 h caused apoptosis in 56.4% of cells and a decrease in mitochondrial membrane potential by 51.9%. Pretreatment with caspase9/3 inhibitors induced more increase in cell viability than treatment with Venenum Bufonis alone. Conclusion Venenum Bufonis can significantly inhibit proliferation in liver cancer cell HepG2 and induce apoptosis. Apoptosis mechanisms may be associated with mitochondrial membrane potential decrease and caspase 9/3 activation.