Abstract: Taking oat, adlay, quinoa, brown rice, yellow millet, barley, highland barley, tartary buckwheat, and rye as raw materials, and wheat as a control, 10 kinds of polysaccharides were obtained by water extraction and alcohol precipitation, respectively. The antioxidant activity of different polysaccharides, the inhibition of HCT116 activity of colon cancer cells and the effect on the growth of probiotics were determined and compared, and the polysaccharides with strong in vitro activity were screened out. In this study, DPPH, ABTS and hydroxyl radical assays were used to study the in vitro antioxidant activities of different polysaccharides, and MTT assay was used to detect the inhibitory effects of different polysaccharides on the proliferation of HCT116 cells at 48 and 72 h. Bifidobacterium longum Reuter, Bifidobacterium breve Reuter, Bifidobacterium adolescentis and Lactobacillus rhamnosus were cultured in vitro to study their effects on the growth of probiotics.The results showed that there were significant differences in the in vitro activities of different coarse cereal polysaccharides. Ten kinds of polysaccharides had scavenging abilities to DPPH, ABTS and hydroxyl radicals. Among them, tartary buckwheat polysaccharide had the strongest scavenging ability to three free radicals, which were 12.76 μmol Trolox/g DW, 39.56 μmol Trolox/g DW and 1615.32 μmol V_C/g DW, respectively. In terms of the effect on the growth of probiotics, 1% concentration of yellow millet, barley and oat polysaccharides could be more easily selected and utilized by Bifidobacterium breve Reuter, Bifidobacterium adolescentis and Lactobacillus rhamnosus. At 48 h, the inhibitory activity of polysaccharide on HCT116 cell proliferation was as follows: Wheat>brown rice>adlay>yellow millet; at 72 h, the inhibitory activity of polysaccharide on HCT116 cell proliferation was as follows: Wheat>adlay>brown rice>yellow millet>barley. The experimental results would provide reference for the quality evaluation of miscellaneous coarse cereals, and provide the basis for the selection of raw materials in the development of functional food.