Abstract: OBJECTIVE To optimize the extraction process of Yuzhang pills and study on its protective effect of acute and chronic liver injury in mice induced by CCl₄. METHODS L₉(3⁴) orthogonal test was used to investigate the ethanol concentration, amount of alcohol, extraction time and times, with the content of offerulic acid as an index. L₉(3⁴) orthogonal test was used to investigate the amount of water,extraction time and extraction times, with the content of polydatin as an index. 0.125%CCl₄(10 mL·kg^-1 intraperitoneal injection)-induced acute liver injury model was established in mice, and the liver protection of Yuzhang pills extract was evaluated by the AST and ALT in serum. The chronic hepatic model was built by hypodermic injection of 20% CCl₄ (5 mL·kg^-1), 5 d one time for 8 weeks, and the liver protection of Yuzhang pills extract was evaluated by the AST and ALT in serum, pathological changes of liver. RESULTS The best extraction process of Chuanxiong Rhizoma and Curumae Radix were using 5 times of 70% ethanol, extract one time for 1.5 h. The best extraction process of Polygoni Cuspidati Rhizoma Et Radix and other herbs were using 10 times of water, extract 3 times for 1.0 h. The high dose group of Yuzhang pills extract could significantly decrease the level of ALT and AST in acute hepatic mice induced by CCl₄(P<0.05). All groups of Yuzhang pills extract could significantly decrease the level of ALT and AST in chronic hepatic mice induced by CCl₄(P<0.05), reduced the liver pathological damage degree. CONCLUSION The optimum extraction process of Yuzhang pills is simple, high extraction yield and stable. Yuzhang pills extract has protective effect on the acute and chronic hepatic injury induced by CCl₄ in mice.