The invention relates to alginate oligosaccharide and its derivatives and application in the treatment of vascular dementia. The alginate oligosaccharide and its derivatives, in particular, the mannuronic acid oligosaccharide formed by the 1,4 glycosidic linkage of β ￣ D ￣ mannuronic acid, or the carboxyl group at the reducing end of the mannuronic acid oligosaccharide and its derivatives, or the pharmaceutically acceptable salt thereof.本發明涉及褐藻膠寡糖及其衍生物及其在治療血管性痴呆方面的應用。本發明所述褐藻膠寡糖及其衍生物特別是β‑D‑甘露糖醛酸通過1，4糖苷鍵連接形成的甘露糖醛酸寡糖或還原端1位爲羧基的甘露糖醛酸寡糖及其衍生物、或其藥學上可接受的鹽。
