Abstract: This paper aimed to optimize the culture technology of polysaccharide, nucleoside and total terpene produced by liquid fermentation of Hericium ericium, and explore its antioxidant activity.With the yield of three active ingredients as the index, the suitable carbon source, nitrogen source, temperature, rotational speed, pH and inoculation amount were screened out through single factor experiment. The comprehensive score of the yield of three active ingredients calculated by entropy weight method was used as the response value. A mathematical model was established by Box-Behnken to determine the optimal conditions for liquid fermentation of Hericium ericium. The antioxidant activity of the fermentation products was evaluated. The results showed that: The optimal carbon source was soluble starch and corn meal, the nitrogen source was yeast extract and yam juice, temperature 23.5 ℃, rotating speed 128 r/min, pH5.9, inoculation quantity 8.5%. Under these conditions, the comprehensive score of liquid fermentation condition of Hericium ericium was 2.090, which was basically consistent with the comprehensive score of 2.164 predicted by the model. The yield of polysaccharide, nucleoside and terpene were 5.12, 1.17 and 0.42 mg/mL. The IC₅₀ values of DPPH scavenging rate of fermentation liquid, fermentation liquid and mycelium (wet) were 166, 237, 53 mg/mL, and the IC₅₀ values of ABTS⁺ scavenging rate were 68, 55, 72 mg/mL. The total reducing capacities at 500 mg/mL were 0.711, 0.708 and 0.841. The study would lay a foundation for the industrialized production of Hericium ericium liquid fermentation.