Abstract: In order to study the antioxidant activity of Tricholoma matsutake polysaccharides (TMP), its antioxidant capacity in vitro was investigated using superoxide anion radical (O₂^－ · ) scavenging capacity, total reducing capacity and ABTS radical scavenging capacity as indicators; and then the mouse model of ethanol oxidative damage was established, and the antioxidant activity of Tricholoma matsutake polysaccharides in vivo were measured by measuring alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (AKP) in the serum of mice and the activity of catalase (CAT), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the liver. In vitro antioxidant results showed that Tricholoma matsutake polysaccharides had better scavenging ability on superoxide anion free radical and ABTS free radical, and the scavenging rate reached 56.67% and 96.60% when the concentration was 1 mg/mL. However, the total reducing ability of Tricholoma matsutake polysaccharides was not obvious. When the concentration was 1 mg/mL, the absorbance value could reach 0.163. Animal experiment results showed that after four weeks of continuous gastric administration, compared with the model control group, Tricholoma matsutake polysaccharides could significantly reduce ALT, AST and AKP viability in mice serum (P<0.05); it also significantly increased the levels of CAT, SOD and GSH-Px in liver (P<0.05), when the content of MDA was significantly reduced (P<0.05). All these indicators showed a dose-response relationship. The experimental results showed that Tricholoma matsutake polysaccharides had certain antioxidant activity, hoping to provide ideas for the subsequent development and application of Tricholoma matsutake polysaccharides.