Abstract: In this paper, a high efficient procedure was studied to extract crude sodium alginate, fucoidin and laminarin simultaneously. Sodium alginate and fucoidin were further purified, the purity of which was demonstrated homogeneously by chromatography on a sephadex G-75 column and acetate cellulose membrane electrophoresis .The experiments compared among soding alginate market Sodium alginate specifically prepared in the experiment and fucoidin.The results of the first two showed that their features on IR and UV spectrum were consistent and their datum on molecular weight, inherent viscocity electrical conductivity and pH were very close. However both differed greatly with fucoidin.

Key words: Polysaccharides of Laminnarin japonica Aresch Sodium alginate Fucoidin Laminarin Extraction Identifcation Physical and chemical characteristics