Objective:This study aimed to explore the relationship between the structure and antioxidant activity of purified red date polysaccharide ZJP-1 and sulfated red date polysaccharide S-ZJP-1.Methods:Using remnant jujube as raw material, jujube polysaccharide (ZJP-1) was purified by hot water extraction, and then separated by DEAE-52 ion exchange chromatography and Sephadex-200 dextran gel column chromatography. Thereafter, red jujube polysaccharide sulfated derivative (S-ZJP-1) was obtain through chlorosulfonic acid-pyridine sulfated modification.Results:Both ZJP-1 and S-ZJP-1 are composed of three monosaccharides: glucose, arabinose, and galactose, but the ratios are different. The two polysaccharides had characteristic absorption peaks of polysaccharides, and S-ZJP-1 had characteristic absorption peaks of sulfate groups, indicating that the sulfation modification was successful. No triple helical structure was found in ZJP-1 or S-ZJP-1, while a sheet-like structure was detected. The results of the activity test confirmed that the polysaccharides ZJP-1 and S-ZJP-1 had significant scavenging activity on DPPH free radicals with reducing ability. When the mass concentration of the two kinds of polysaccharide was 0.5 mg/mL, the DPPH free radical scavenging activities were 40.4% and 47.6%, and the reducing ability is 0.419 and 0.531, respectively.Conclusion:The sulfate- modification jujube polysaccharide has higher antioxidant activity and is a good natural antioxidant.