Abstract: Objective:To observe the protective effect of Schisandra chinensis polysaccharide(SCP)on acute liver injury induced by acetaminophen(APAP)in mice and explore its effect on hepatocyte apoptosis. Methods:The acute liver injury model in mice was established by intraperitoneal injection of APAP(250 mg/kg). 50 ICR mice were randomly divided into control group,model group(MOD)and 25,50 and 100 mg/kg SCP group. The levels of alanine aminotransferase(ALT)and aspartate aminotransferase(AST)in serum of mice,the levels of glutathione(GSH)and malondialdehyde(MDA)in liver homogenate of mice significantly measured. HE and Hoechst 33258 staining were performed for observing the change of hepatic pathology and apoptosis of hepatocyte,respectively. The expressions of apoptosis-related proteins JNK,Bax,Bcl-2 and Cleaved caspase-3 in liver tissue were detected by Western blotting analysis. Results:Compared with the MOD group,the levels of ALT and AST in serum of mice decreased(p<0.05)in 25 and 50 mg/kg SCP groups and extremly significantly decreased(p<0.01)in 100 mg/kg SCP group. The level of GSH was significantly increased(p<0.05)and the level of MDA was reduced(p<0.05)in liver tissue in 50 and 100 mg/kg SCP groups. SCP could improve hepatocyte degeneration and necrosis,inflammatory infiltration and inhibit hepatocyte apoptosis. Compared with the MOD group,SCP pretreatment could significantly decrease the expressions of p-JNK(p<0.05),decrease significantly Cleaved caspase-3 and Bax,and increase Bcl-2 protein expression(p<0.01). Conclusion:SCP has a protective effect on APAP-induced liver injury in mice,and its underlying mechanism might be related to the inhibition of hepatocyte apoptosis.