Abstract: In order to explore the effect of probiotic fermentation on the extraction of crude polysaccharide from Hericium erinaceus and its antioxidant activity, the effects of the extraction rates of water extract of Hericium erinaceus fermented by Lactobacillus acidophilus, Bifidobacterium longum and Saccharomyces cerevisiae (high sugar type) and the content of polysaccharide were investigated, and the effects of different probiotic fermentation on the total antioxidant capacity of crude polysaccharide and the infrared spectrum structure were analyzed. The results showed that: compared with the fermentation without probiotics, the extraction rates of water extract of Hericium erinaceus fermented by Lactobacillus acidophilus, Bifidobacterium longum and Saccharomyces cerevisiae (high sugar type) decreased by 7.50%, 3.50% and 10.10%, respectively, but the content of crude polysaccharide in the extract increased by 25.46%, 26.98% and 20.20%, respectively. The extraction rate of crude polysaccharide fermented by Bifidobacterium longum was the highest (11.55%). The single factor and orthogonal experiments were used to optimize the fermentation process of Hericium erinaceus by probiotics. The optimum technological conditions were as follows: the addition amount of Bifidobacterium longum was 20%, the fermentation time was 4 h, and the fermentation temperature was 42℃. Under the optimum conditions, the extraction rate of water extract was 27.85%, the content of crude polysaccharide in the extract was 62.87%, and the extraction rate of crude polysaccharide was 17.51%. After the fermentation by Saccharomyces cerevisiae, the total antioxidant capacity of crude polysaccharide from Hericium erinaceus was the highest, up to 6.07 umol·g^-1. There was no significant difference in the total antioxidant capacity between the crude polysaccharides fermented by Bifidobacterium longum and the crude polysaccharides without the probiotic fermentation (P<0.05). The fourier transform infrared spectroscopy of crude polysaccharides of Hericium erinaceus after the fermentation of different probiotics were basically similar to those of unfermented Hericium erinaceus, and the peak position was slightly shifted with similar functional groups.