Preparation method of seaweed extract and seaweed extract

The present invention provides a seaweed extract manufacturing method comprising: (A) a polysaccharide extract manufacturing step for manufacturing polysaccharide containing extract by a hot water extract of seaweed; (B) a polysaccharide breakdown enzyme culture medium manufacturing step for manufacturing a culture medium containing a polysaccharide breakdown enzyme by removing a fungus body after culturing a microorganism for producing the polysaccharide breakdown enzyme; and (C) an enzyme reaction step for performing an enzyme reaction by mixing the polysaccharide extract manufactured in step (A) and the culture medium containing a polysaccharide breakdown enzyme manufactured in step (B); a seaweed extract, a composition for cosmetics, and a food composition. The present invention has an advantage of providing a seaweed extract containing polyphenol by being easily and simply manufactured. [Reference numerals] (AA) Polysaccharide extract manufacturing step; (BB) Polysaccharide breakdown enzyme culture medium manufacturing step; (CC) Enzyme reaction step; (DD) Refinement step