Objective To explore the protective mechanism of Potentilla anserina polysaccharide (PAP) on acute liver injury induced by D-galactosamine (D-GlaN) in mice. Methods Sixty Kunming mice were randomly divided into normal control group, model group, bifendate group (positive control) and PAP (50, 100, 200 mg/kg) treated groups, with 10 mice in each group. After treatment with normal saline, bifendate and PAP (50, 100, 200 mg/kg) for 7 days, the mice in normal control group were injected intraperitoneally with normal saline, and those in the other 5 groups were injected intraperitoneally with D-GlaN to establish acute liver injury models. All the animals were sacrificed 24 h after model establishment, and the levels of hepatic superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), and glutathione peroxidase (GSH-Px) were determined. Results Compared with normal control group, the model group had significantly increased hepatic MDA level(P<0.05) and significantly decreased activities of hepatic SOD, GSH-Px and level of GSH (P<0.05, P<0.01). Compared with the model group, bifendate and 50, 100, 200 mg/kg PAP significantly decreased hepatic MDA level (P<0.05), increased the activities of hepatic SOD, GSH-Px and level of GSH (P<0.05, P<0.01) in mouse acute liver injury model. Conclusion PAP can protect the liver of mice with acute liver injury induced by D-GlaN, which is probably through scavenging free radicals, protecting cell membranes and inhibiting lipid peroxidation.