The effects of acid pretreatment and enzymolysis with alginate lyase and cellulasedouble on extracting soluble sugars from L. japonica were investigated. The results showed that 100 mesh,5%( w / v) of kelp powder was suitable for successive saccharification via enzymatic hydrolysis using both alginate lyase and cellulase. Subsequently, the kelp extract with highest concentration of reducing sugars among all the treatments was applied for ethanol fermentation. Zymobacter palmae and Pichia angophorae were used as fermentative strains in fermentation of the kelp extract and the final ethanol yields were 4. 57g / L( 5. 8mL / L) and 2. 68g / L( 3. 4mL / L) respectively. The highest ethanol concentration of 4. 57g / L reached 28. 99% of the theortical yield.