In order to further clarify the mechanism of the ethyl acetate extract of S. emarginatum in promoting cell apoptosis, RT-PCR was used to detect the effect of the ethyl acetate extract of S. emarginatum on the expression of Bcl-2 mRNA, Bax mRNA and Caspase-3 mRNA in liver cancer HepG2 cells. The gene discussed is CASP3; the disease is liver cancer.