An apparatus for fabrication of a magnesium-based carbon nanotube composite material, the apparatus includes a thixomolding machine, and a feeding device. The thixomolding machine includes a heating barrel, a feeding inlet, a nozzle, a heating portion, and a plunger. The heating barrel includes a first end and a second end. The feeding inlet is disposed at the first end. The nozzle is disposed at the second end. The heating portion is disposed around the heating barrel. The plunger is disposed at a center of the heating barrel. The feeding device includes a hopper; an aspirator connected to the hopper, a first container, and a second container. The hopper is in communication with the first container and the second container. A method for fabricating a magnesium-based carbon nanotube composite material is also provided.