By according to the predecessors' research results and collecting in Fujian coastal areas and buying in market we obtains 8 kinds of sea algae. Crude polysaccarides are extracted from the 8 kinds of sea algae {Rhizodonium implexum (Dillw.) kittz, Enteromorpha tubulosa kutz., Porphyra haitanensis, Sargassum vachellianum Grev., Laminaria japonica, Gracilaria verrucosa (Huds.) Paperfuss, Sargassum fusiforme (Harve.) Setch,. Ulva pertusa Kjellm) by water, acid and alkali and we account the rate of extracted. Af...