Sodium Alginate is a kind of natural polysaccharide consisted in brown seaweed as a natural product generated from alginic acid in seaweed and minerals from the sea. As the hydrophilic gel, sodium alginate is the prevailing salt of algin, which is apt to form thick solutions. With the properties of thickness and stability, sodium alginate can be used as thickener and stabilizer in food stuff, printing paste and an oil extraction agent.