Hepatocellular carcinoma (HCC) is the second and sixth leading cause of cancer death in men and woman in 185 countries statistics, respectively. n-Butylidenephthalide (BP) has shown anti-HCC activity, but it also has an unstable structure that decreases its potential antitumor activity. The aim of this study was to investigate the cell uptake, activity protection, and antitumor mechanism of BP encapsulated in the novel liposome LPPC in HCC cells. BP/LPPC exhibited higher cell uptake and cytotoxicity than BP alone, and combined with clinical drug etoposide (VP-16), BP/LPPC showed a synergistic effect against HCC cells. Additionally, BP/LPPC increased cell cycle regulators (p53, p-p53, and p21) and decreased cell cycle-related proteins (Rb, p-Rb, CDK4, and cyclin D1), leading to cell cycle arrest at the G(0)/G(1) phase in HCC cells. BP/LPPC induced cell apoptosis through activation of both the extrinsic (Fas-L and Caspase-8) and intrinsic (Bax and Caspase-9) apoptosis pathways and activated the caspase cascade to trigger HCC cell death. In conclusion, the LPPC complex improved the antitumor activity of BP in terms of cytotoxicity, cell cycle regulation and cell apoptosis, and BP/LPPC synergistically inhibited cell growth during combination treatment with VP-16 in HCC cells. Therefore, BP/LPPC is potentially a good candidate for clinical drug development or for use as an adjuvant for clinical drugs as a combination therapy for hepatocellular carcinoma.