The flocculating extraction process of seaweed polysaccharide includes: circular supersonic crushing or water boiling lixiviation to obtain seaweed polysaccharide liquid, flocculation of flocculation in electric field of the seaweed polysaccharide liquid inside one ractor by adding flocculating agent and at 20-60 deg.c, pH 5-8 and 300-1500 rpm stirring speed to extract coarse seaweed polysaccharide product, purification or stoving of the coarse seaweed polysaccharide product to obtain seaweed polysaccharide product. The said process uses small amount of flocculating agent and thus low extraction cost accounting for about 0.1 cost of that in alcohol process. |