The extraction temperature, ratios of water to material and extraction time were taken as the influencing factors, and the extraction rate of polysaccharides from Clinacanthus nutans was taken as the evaluation index to carry out single factor experiment, and Box-Behnken response surface methodology was used to optimize the extraction process on the basis of single factor test results. The results showed that the best extraction conditions of polysaccharides from Clinacanthus nutans were as follows: the ratio of material to liquid was 1:31 (g/mL), the extraction temperature was 92 ℃, the extraction time was 1.6 h. and the extraction rate was 3.40%. The antioxidant activity test showed that the polysaccharide of Clinacanthus nutans had good scavenging ability in ABTS anion free radical and DPPH free radical and had certain scavenging ability on hydroxyl free radicals