To optimize the ultrasonic extraction process of Bletillastriata polysaccharides, compare the content of Bletillastriata polysaccharides from different origins, and investigate the stability and antioxidant activity of Bletillastriata polysaccharides. Methods:Polysaccharide yield rate was taken as the investigation index, the material-liquid ratio, ultrasonic temperature, and ultrasonic time was as the investigation factors, L9 (34) orthogonal test was designed to optimize the ultrasonic extraction process of Bletillastriata polysaccharides; the content of Bletillastriata polysaccharides was determined by phenol-sulfuric acid method. the differences in polysaccharide content of Bletillastriata polysaccharides in Hanzhong in Shaanxi, Pu'er in Yunnan, Hongjiang in Hunan and Mianyang in Sichuan were investigated. The stability of Bletillastriata polysaccharides was investigated by chemical methods, and the clearance rate of 1, 1-diphenyl-2-picridyl radical (DPPH·) and hydroxyl radical (·OH) by Bletillastriata polysaccharides was compared to evaluate its in vitro antioxidant activity. Results:The optimum extraction conditions were：solid/liquid ratio 1:25 (g/mL), ultrasonic temperature 80 ℃, ultrasonic time 10 min. The content of Bletillastriata polysaccharides in Mianyang in Sichuan was the highest, reaching 60.81%, Hongjiang in Hunan Province was the second, Puer in Yunnan Province was the lowest; the stability test showed that the stability of Bletillastriata polysaccharides in citric acid and neutral solution was better than that in sodium benzoate, acid or alkaline solution. Bletillastriata polysaccharides can effectively remove DPPH and hydroxyl free radicals, and have potential antioxidant activity in vitro. Conclusion:Study on the optimization of the extraction process of Bletillastriata polysaccharides and its antioxidant activity can provide a reference for the extraction and comprehensive utilization of Bletillastriata polysaccharides.