A facile and controllable route for fabricating multilayered graphene was provided using CO2 as a carbon source. A typical multilayered graphene structure was obtained with the reaction between CO2 and magnesium metal. The reaction was carried out under different CO2 gas flows, reaction temperatures, and reaction times with two types of metal Mg (Mg powder and Mg ribbon). Moreover, the effect of different concentrations of HCl solution for sample post-processing was discussed in this study. The results of transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), Raman spectroscopy and X-ray powder diffraction (XRD) confirm the formation of multilayered graphene. This work proposed a new method for a controllable way to produce multilayered graphene with gaseous CO2 as a carbon source.