Magnesium-based hydrogen storage alloys are considered to be one of the most valuable metal hydrogen storage materials ,due to their extremely high hydrogen storage capability ,low flat roof of absorbing or expanding hydrogen and rich natural resources. The researches on magnesium2based hydrogen storage alloys ,especially the basic research on Mg2Ni2based hydrogen storage alloy are summarized. Furthermore ,the advantages and disadvantages of magnesium-based hydrogen storage alloys are discussed ,at the same time some of the scientific problems and the research trend are also put forward.