The invention provides an enzymolysis treatment method of algae. The method comprises the steps of material preparation, pretreatment, enzyme treatment and centrifugating. In the enzyme treatment step, the adopted enzyme is a composite enzyme which comprises proteinase, cellulase and pectinase in a mass ratio of 3:1:2. The proteinase is any one of papain, bromelin, carboxypeptidase and chymopapain. The cellulase is any one of cellobiohydrolase, endoglucanase, beta-glucosaccharase and cellobiase. The pectinase is any one of protopectinase, lyase and polygalacturonase. According to the enzymolysis treatment method of algae, the extraction rate of sodium alginate is 38.0-50.9%, and the extraction rate of alga glycine is 7.5-11.8%.