Abstract: OBJECTIVE To investigate the protective effect of 18α-glycyrrhizic acid solid lipid nanoparticles (18α-GL-SLN) on acute liver injury in rats. METHODS Acute liver injury in rats was caused by CCl₄, and the protective effect of 18α-GL-SLN was evaluated with biochemical indicator and pathological change. RESULTS Compared with model group, different dosages groups of 18α-GL-SLN and 18α-GL group all obviously degraded the level of ALT, AST, TBil, γ-GT and ALP, it had statistical significance( P <0.05). This showed that the three groups of 18α-GL-SLN and the group of 18α-GL all had protective effect on acute liver injury in rats, and the effect of middle and high dose groups of 18α-GL-SLN were even better than group of 18α-GL( P <0.05). The pathological changes revealed that liver injury was relieved in all treated groups. CONCLUSION 18α-GL-SLN has the protective effect on acute liver injury in rats, and it resulted a better effect than 18α-GL.