Metallic Mg is an ideal anode material for rechargeable magnesium-ion batteries (RMBs) due to its high volumetric energy density, low safety concern, two-electron redox as well as the large abundance and environmental friendliness of magnesium element. However, challenges such as interfacial passivation, formation of dendrites, and large volume changes of electrode hinder the development and practical application of Mg metal anode. To address these issues, many modification strategies have been proposed in the past several years, such as modifying liquid electrolytes, designing artificial solid electrolyte interphase (SEI), constructing interfacial alloy layer, fabricating 3D scaffolds, utilizing solid electrolytes, developing advanced characterization methods, and deepening theoretical study. Here a detail review is presented to summary and analyze these modification strategies. Meanwhile, some perspectives and outlooks are put forward. This review can inspire related researchers and promote the application of Mg metal anode in rechargeable Mg batteries.