Purpose of this article is to investigate technology condition of laminarin extracting from Laminaria japomica Aresch, yield rate of laminarin extracting from Laminaria japomica Aresch as standard, using Orthogonal designing Experiment, optimizing extract methods. the maximum yield of the polysaccharide was obtained when pH scale is2.0; extract temperature is 70°C; ratio of solvent to raw material is 50∶1(g/ml); duration of extraction is 2 hours. This extract technology was reasonable and feasible, it was suitable to extract laminarin from Laminaria japomica Aresch.