Calcium alginate is the calcium salt of alginate. Alginate is made from seaweed plants, such as Sargassum, Laminaria japonica and kelp, which are abundant in China. The main functions of calcium alginate are as follows: (1) calcium alginate sponge: calcium alginate is mainly used in the production of calcium alginate sponge, which can be used for hemostasis of skin injury and wound bleeding. When calcium alginate sponge is applied to the wound, calcium ions are exchanged with the sodium ions in the wound exudates and blood, releasing calcium ions and forming a thin layer of gel on the wound surface. Due to the release of calcium ion, the formation of blood clot in the end of capillary is accelerated, so as to achieve rapid hemostasis. Due to the formation of gel layer on wound surface, it can protect the wound and maintain a certain humidity and temperature. It can create a good microenvironment for wound healing and promote wound healing. 2) stabilizer and gelling agent: the ability and intensity of alginate forming gel are related to Ca2+. It interacts with calcium ions in milk to form calcium alginate, which causes a series of complex reactions of milk proteins. Calcium alginate can keep the shape of ice cream well, especially the ice cream kept for a long time. It is very effective to prevent shrinkage and tissue sanding. It has synergistic effect with Ca2 + and pectin（ 3) Immobilized fermentation of brewer's yeast: put brewer's yeast into the sodium alginate solution dissolved in wort, and then drop it into the calcium chloride solution dissolved in wort to form calcium alginate particles containing yeast cells and immobilize yeast cells.