Abstract: This study was conducted to investigate the fermentation conditions of corn cob based on the yield of ploysaccharides,and determine the monosaccharide components as well as evaluate in vitro probiotic activity of corn cob ploysaccharides. The results showed that optimal conditions for fermentation of corn cob were total inoculum size of 8%,wheat bran addition of 10%,cellulase supplementation of 500 U/g,solid to liquid ratio of 1:1.25,fermentation time of 96 h,and incubation temperature of 35℃,respectively.The concentration of corn cob polysaccharide was 162.61 mg/g by phenol sulfuric acid method,which was 20.16% higher than unfermented corn cob polysachharides contents.The monosaccharide composition of corn cob polysaccharides was determined by precolumn derivatization HPLC. The results showed that xylose,arabinose,galactose and mannose contents in fermented corn cob were increased by 152.17%,118.12%,64.73% and 36.30% than unfermented corn cob,respectively,while glucose contents was decreased by 57.29%. Prebiotic activity study showed that corn cob crude ploysaccharides included in the culture medium had a higher proliferation effect on Lactobacillus plantarumand Streptococcus thermophiles than only glucoseas carbon source. Furthermore,compared with the unfermentated polysaccharides,fermentated corn cob crude ploysaccharides have more superior prebiotic effect on the two probiotics.In summary,yield of corn cob ploysaccharides was increased and monosaccharide components were changed,as well as probiotics effect were improved by solid-state fermentation of corn cob.