Abstract: To optimize the key process parameters for extracting crude polysaccharides from Hericium erinaceus via compound probiotic fermentation, aiming to enhance the extraction rate of crude polysaccharides and clarify their antioxidant activity. Single-factor and orthogonal experiments were employed to investigate the effects of compound probiotic strain ratio, addition amount, temperature, time, and initial pH on the extraction rate of Hericium erinaceus crude polysaccharides, as well as to analyze the impact of compound probiotic fermentation on the antioxidant activity of crude polysaccharides. The results showed that compared with non-probiotic fermentation, the compound probiotics（Lactobacillus plantarum∶Bacillus subtilis∶Streptococcus thermophilus at a ratio of 1∶2∶1）resulted in the highest crude polysaccharide extraction rate（16.11%）. Through single-factor and orthogonal experiment optimization, under the conditions of compound probiotic addition amount of 25%, fermentation temperature of 34 ℃, fermentation time of 12 h, and initial pH of 6.5, the extraction rate of Hericium erinaceus crude polysaccharides could reach 18.51%, while maintaining good in vitro antioxidant activity（at a mass concentration of 3.0 mg·mL⁻¹, the scavenging rates for DPPH, hydroxyl, and ABTS free radicals were 71.26%, 86.90%, and 84.59%, respectively).