Abstract:After the pretreatment of chlorella algae powder solution by ultrasonic method，the polysaccharide was extracted by hot water extraction with compound enzyme method，and the extraction conditions of polysaccharide were optimized by response surface methodology.By single factor test and response surface analysis，the results showed that the optimum extraction conditions were as follows：the ratio of solvent to materia was 20 ∶1（mL/g），the amount of compound enzyme was 1.45%，the pH value was 5，and the enzymolysis temperature was 39℃.Under this condition，the extraction rate of polysaccharides from chlorella was 6.56%.