Enteromorpha prolifera is a seaweed species that is responsible for widespread green tides. It is also a seafood species and contains relatively high levels of protein, fatty acids and trace elements. In this study, fresh E. prolifera was treated by protease, cellulase, formic acid and natural fermentation, before being used as feed for young sea cucumber Apostichopus japonicus. The protease treated E. prolifera obtained good growth in sea cucumbers. It is suggested that, after proper treatment and processing, E. prolifera may be a good feed source for sea cucumbers, and this is a feasible way to utilize this green tide species as a resource.