Abstract: Objective To investigate the synergistic killing effect and mechanism of matrine combined with X-ray on human hepatic cancer cells HepG2. Methods MTT and ELISA were used to detect cell viability and apoptosis, respectively. Real-time RT-PCR was used to examine Bcl-2 and Bax expression. Western blot was used to determine the expression of caspase-9, pro-caspase-9 and cytochondrial-C. NobiFlow GOT - IFCC and NobiFlow LDH - L were used to measure the levels of LDH and AST. Results Pretreatment of matrine (3 mg/ml) for 12h significantly increased the killing effect of X-ray on HepG2 cells, induced cells apoptosis, inhibited the expression of Bcl-2, and enhanced the levels of cytochondrial-C and caspapase-9 in the cytoplasm. However, the combination of matrine and X-ray did not alter cell morphology, LDH, or AST expression in human hepatocytes. Conclusion The combination treatment of matrine and X-ray could synergistically inhibit the growth of HepG2 cells by inducing cell apoptosis, without enhancing the damage to human hepatocytes.