Fucoidan, a complex polysaccharide sulfate, which contains fucose polysaccharide (FCSPs), was found in marine algae. Fucoidan has many valuable biological activities such as anti-cancer, anti-inflammatory, antioxidant, immunity... Ceratophyllum submersum alga contains bioactive ingredients, notably fucoidan. This study investigates the effects of solvents on removing the impurities, the effects of enzyme cellulase and microwave on fucoidan extraction from C. submersum (which was collected in Soc Trang province). The study also investigates the solvent for removing the impurities before fucoidan extraction - system 1 (methanol: chloroform: water), system 2 (hexane; acetone; 80% alcohol; ethanol: water: formaldehyde) as well as the effects of enzyme cellulase, microwave on fucoidan extract. The results have shown that the fucoidan content which was treated with system 2, was 568,442±9,721 (µg/gdm) higher than that of using system 1 (422,127±11,554 µg / gdm). The content of fucoidan is obtained with enzyme support (1022,22±8,680µg/gdm), microwave support (992,77± 5,230µg/gdm), enzyme and microwave combination (1484,82± 3,403 µg/gdm).