Objective This research aims to improve the bioavailability and anti-hepatocellular carcinoma (HCC) efficacy of Ginsenoside Rg3 by modification with poly (lactic acid hydroxyacetic acid)-poly(ethylene glycol) (PLGA-PEG). Methods PLGA-PEG-Rg3 was obtained by emulsification and evaluated it physiochemical characterization by FTIR, SEM, laser particle-size analyzer and HPLC. The effect of the PLGA-PEG-Rg3 and Rg3 on HepG2 cells was compared in vitro studies, including cell proliferation, transwell and a series of apoptosis detection, and in-situ HCC model. Results The PLGA-PEG-Rg3 were 122 nm in size and 0.112 in polydispersity index with sustained release profile in vitro. Compared to Rg3, PLGA-PEG-Rg3 was more effective in suppressing HepG2 growth and inducing apoptosis by the mitochondrial apoptosis pathway in vitro. And PLGA-PEG modification enhanced the liver-targeting ability and drug circulation time of Rg3 in vivo, resulting in PLGA-PEG-Rg3 possessing superior performance in inhibiting tumor growth and prolonging the survival time of tumor-bearing mice than Rg3. Conclusions Overall, these results showed PLGA-PEG-Rg3 enhanced the anti-tumor effect of Rg3 in HCC.