Study on optimization of extraction technology of Epimedium Polysaccharide and effect of its immunomodulatory function. In order to optimize the extraction process of Epimedium polysaccharides and the effect of Epimedium polysaccharides on enhancing immune function. The cellulase-assisted hot water extraction method was used. On the basis of the single factor test results, the enzyme concentration, enzyme extraction temperature, and enzyme extraction time were selected as independent variables. The three-level Box-Behnken response surface design optimizes the extraction process of Epimedium polysaccharides. The ethanol precipitation method is based on the single factor test, and the concentration ratio, ethanol concentration, ethanol volume multiple, and alcohol precipitation time are selected as independent variables. The orthogonal experimental design of L9 (34) was used to optimize the optimal alcohol precipitation conditions of Epimedium polysaccharides. The effect of NO on macrophage release was measured by Griess-Saltzman. And the proliferation of chicken spleen lymphocytes was examined by MTT. The results showed that the enzymatic concentration was 110 U/μL, the enzymatic extraction temperature was 60°C, and the enzymatic extraction time was 100 min. The extraction rate of Epimedium polysaccharides was the highest, reaching 10.06%, and the enzymatic extraction temperature had the greatest influence on the polysaccharide extraction rate. The concentration ratio is 1 : 2, the ethanol concentration is 800 mL/L, the ethanol volume is 4 times, and the alcohol precipitation time is 12 h; each ethanol concentration of alcoholic precipitated epimedium polysaccharide has good activity, 500 mL/L-ethanol alcohol precipitation has the best polysaccharide activity. The results also showed that Epimedium polysaccharide had a good stimulating effect on macrophages; it promoted the proliferation of chicken spleen lymphocytes.