The present invention relates to a magnesium-based composite material includes at least two magnesium-based metallic layers; and at least one magnesium-based composite layer respectively sandwiched by the at least two magnesium-based metallic layers. The present invention also relates to a method for fabricating a magnesium-based composite material, the method includes the steps of: (a) providing at least two magnesium-based plates; (b) providing a plurality of nanoscale reinforcements; (c) sandwiching the nanoscale reinforcements between the at least two magnesium-based plates to form a preform; and (d) hot pressing the preform to achieve the magnesium-based composite material.