Due to antitumor and antioxidant activities, there has been increasing interest in fucoidans, sulfated polysaccharides, from brown algae. Currently, the classic hot water extraction and acid extraction are time-consuming, and can cause the partial cleavage of sulfate esters, leading to bioactivity loss. The present study developed a novel process for extracting fucoidans from Laminaria japonica with 0.5% ethylenediaminetetraacetic acid at 70 degrees C. Crude fucoidans (CFs) obtained with a yield (similar to 16%) was purified to different fractions of F1, F2 and F3. The fractions displayed similar anticancer activity against Hela cells. Due to the differences in sulfate content, molar ratio of sulfate to fucose and monosaccharide composition, F1 and F2 exhibited stronger antioxidant ability than CFs and F3. This novel extraction provides an efficient procedure for extracting fucoidans from brown seaweeds with high extraction yield and removing pigments with one single step.