Abstract: Objective: To study the extraction kinetics and antioxidant activity of polysaccharides from seeds of Gleditsia sinensis. Methods: Based on Fick’s first law,the extraction kinetic model was established,and the structure of polysaccharides from seeds of Gleditsia sinensis was analyzed by infrared spectrum.The scavenging ability of polysaccharides from seeds of Gleditsia sinensis on ABTS free radical,hydroxyl autoradical,1,1-diphenyl-2-trinitrophenyl hydrazine(DPPH)free radical and superoxide anion radical was determined to evaluate its antioxidant activity. Results: The results showed that the calculated value of the kinetic model was in good agreement with the actual measured data,which was in accordance with the first-order extraction kinetic model,and the activation energy was 15.023 kJ/mol.The infrared spectrum showed that polysaccharides from seeds of Gleditsia sinensis contained mannose,which was β-type pyran polysaccharide. The antioxidant activity of polysaccharide increased with the increase of concentration. When the concentration was 5 mg/mL,the scavenging rates of ABTS,DPPH and superoxide anion were 71.82%,83.36%,84.00% and 86.11%,respectively. Conclusion: The kinetic model of the polysaccharide extraction was established,and polysaccharides from seeds of Gleditsia sinensis had good antioxidant activity.