The invention relates to a rechargeable 
magnesium battery 
cathode material. The percentages by weight of the chemical components of the rechargeable 
magnesium battery 
cathode material are: 80 to 90 percent of 
titanium dioxide, 5 to 10 percent of 
activated carbon and 5 to 10 percent of carbon nanotubes. A preparation method for the rechargeable 
magnesium battery 
cathode material mainly includes the following steps: the 
powder of three types of elements, i.e. 
titanium, 
aluminium and carbon, is sintered by spark 
plasma, so that Ti3AlC2 is synthesized; Ti3C2Tx is obtained by 
hydrofluoric acid erosion; Ti3C2Tx is put into glucose or 
sucrose solution, and 
activated carbon-coated Ti3C2Tx is obtained by 
hydrothermal carbonization; aqueous 
hydrogen peroxide solution is added into 
activated carbon-coated Ti3C2Tx, and after oxidation in a 
hydrothermal reaction kettle, activated carbon-coated two-dimensional layered 
titanium dioxide is obtained; the activated carbon-coated two-dimensional layered 
titanium dioxide is mixed with the carbon nanotubes, an appropriated amount of deionized water is added, and after stirring and 
ultrasonic oscillation, the rechargeable 
magnesium battery cathode material is obtained. The rechargeable 
magnesium battery cathode material obtained by the invention is nontoxic, harmless, safe and environment-friendly, the structure is novel, and both the cycle performance and rate capability of the 
magnesium battery are greatly enhanced.