Abstract: Using the yield of crude polysaccharides from Grateloupia filicin as index, this thesis compared and analyzed several extraction methods, including water extraction, alkali extraction, enzymatic hydrolysis and microwave-assisted extraction. Using the yield of polysaccharides from Grateloupia filicin as index, this thesis studied the factors that influenced the index, including treatment temperature, time and S/L ratio, and through the single-factor experiment and the orthogonal test, the optimal combination of extraction technology of polysaccharides was established. The results indicated that water extraction was the best method to extract polysaccharides and the extraction efficiency was 55.64%, the optimal extraction technology conditions were the temperature of 100℃,time of 5 h,solid-liquid ratio of 1:60, the yield of polysaccharides up to 59.42%.