〔Abstract〕 Objective To investigate the effect of BET family small molecule inhibitor JQ1 combined with sorafenib on the proliferation and apoptosis of liver cancer cells and its mechanism. Methods The proliferation inhibition rate of sorafenib, JQ1 and JQ1 combined with sorafenib on HepG2 and Bel-7402 human liver cancer cells was detected by MTT assay, the change of apoptosis rate was detected by flow cytometry, the expression of c-MYC, Bcl-2 and BIM proteins was detected by Western blot. Results Compared with sorafenib and JQ1 alone, the proliferation inhibition rate and apoptosis rate of liver cancer cells increased when treated with JQ1 combined with sorafenib, the expression of c-MYC and Bcl-2 protein was down-regulated and the expression of BIM protein was up-regulated after treated with JQ1 combined with sorafenib on liver cancer cells. Conclusion A certain concentration of JQ1 can enhance the proliferation inhibition and apoptosis effects of sorafenib on liver cancer cells, and its mechanism may be related to the down-regulated expression of c-MYC and Bcl-2, and the up-regulated expression of BIM.