The extraction technology of polysaccharide from salvia miltiorrhiza f. alba by optimized complex enzyme method was studied to evaluate its antioxidant activity. Taking polysaccharides extraction rate as response value, the ratio of water to material, enzymolysis temperature and time, and complex enzyme concentration (papain:cellulase:pectinase=2∶2∶1) as experimental factors, the mathematical model was established by response surface method. The extraction conditions were optimized. The physico-chemical characteristics of the polysaccharide and the free radical scavenging activity to DPPH and·OH were analyzed. The result showed that according to quadratic regression model response surface analysis the effect of the 4 factors on polysaccharide yield was decreased in the order of ratio of water to material, extraction time, extraction temperature and complex enzyme concentration. The optimal conditions were that the concentration of complex enzyme was 8.0 mg/mL, extraction time was 70 min, the ratio of water to material was 45∶1 mL/g, and extraction temperature was 52 ℃. Under the optimal conditions, the experimental extraction rate was 13.36%, the predicted extraction rate by mathematical model was 13.70%. The difference between them was less than 5%. The sample was levogyration and acidity polysaccharide, and soluble in water easily with relatively strong antioxidant activity, the IC50 for DPPH and ·OH were 0.969 mg/mL and 3.114 mg/mL, respectively, which was weaker than those of vitamin C. The polysaccharides from salvia miltiorrhiza f. alba extracted by optimal complex enzymatic extraction technology optimized by response surface methodology showed relatively strong antioxidant activity.