Abstract: Taking permeate liquid in the process of extracting heparin from porcine intestinal mucosa as raw material, the extraction process of dermatan sulfate was optimized to explore the antioxidant capacity of dermatan sulfate. Taking the concentration of dermatan sulfate as the detection indicator, screening the best enzyme for enzymatic hydrolysis, on the basis of single factors, the high-pressure enzymatic hydrolysis process was optimized by Box-Behnken response surface test, the best macroporous resins were screened, the dynamic adsorption and elution conditions were optimized to purify dermatan sulfate, and investigating antioxidant activity in vitro. The results showed that: Under the optimal enzymatic hydrolysis conditions, temperature 56 ℃, pH9.0, time 8.4 h, and pressure 135 MPa, the measured concentration of dermatan sulfate was 13.05 ng/mL, which was close to the model value. D312 resin at 1.5 BV/h flow rate, 4% NaOH 1.5 BV/h flow rate elution and purification effect was the best, and high-performance gel permeation chromatography determination purity could reach 73.32%. The antioxidant capacity of dermatan sulfate was positively correlated with the concentration, the scavenging rate of DPPH free radical was 36.29% at 2.4 mg/mL, showing a certain scavenging ability. For ·OH, the scavenging ability was stronger at 2.4 mg/mL, which was 68.2%, and the total reducing power was 0.22 at 2.4 mg/mL. This study would provide a theoretical basis for the separation and purification of dermatan sulfate and its development and utilization in terms of antioxidant function.