In this study， the samples of crude polysaccharides were prepared from 8 kinds of fermented bean flour by Lactobacillus casei， and the yield， structural characteristics and antioxidant activities of these crude polysaccharides were compared and analyzed. The results showed that the yields of crude polysaccharides were between 1.07% and 11.42%， and the yield of crude polysaccharides from fermented red bean flour showed the highest value (11.42%). All of the crude polysaccharides contained uronic acid， and the uronic acid in crude polysaccharides from fermented kidney bean flour showed the highest content 7.46%. The molecular weight of main polysaccharides was between 0.35-36.67 ku， and the crude polysaccharides from fermented mung bean flour contained the most types of polysaccharide molecules. The crude polysaccharides were composed of mannose， glucuronic acid， glucose， galactose， xylose and arabinose with different contents. The apparent form of crude polysaccharides was flaky， loose and irregular， and the crude polysaccharide from fermented mung bean flour showed the highest degree of looseness. The infrared spectra of crude polysaccharides from 8 kinds of fermented bean flour was consistent with the characteristic absorption of polysaccharide compounds. The crude polysaccharides from 8 kinds of fermented bean flour showed different antioxidant activities: the IC50 values for scavenging DPPH radical of fermented lentil and crude mung bean polysaccharides were 0.07 mg/mL and 0.98 mg/mL， respectively， the crude polysaccharides from fermented lentil flour had the best scavenging effect on DPPH radical. The IC50 value for scavenging ABTS radical cation of crude polysaccharides from fermented mung bean flour was 0.67 mg/mL， which showed the best scavenging ability for ABTS radical cation and crude polysaccharides from mung bean flour also showed the highest reduction ability to iron ions. Compared with the crude polysaccharides from 8 kinds of fermented bean flour by Lactobacillus casei， the crude polysaccharides from fermented mung bean flour showed the best antioxidant activity. It provided an important theoretical basis for the nutritional evaluation of fermented bean foods by Lactobacillus casei.