This article considers ignition and combustion of single particles of magnesium and aluminum in carbon dioxide at pressures 0.1-2 NPa. An experimental setup with an electrodynamic levitator inside a high-pressure chamber was employed. The CO2-laser was used for heating to ignition of the particles. The results show that ignition mechanisms of Mg and Al in CO2 are different Experiments with Mg indicate the existence of the critical partial pressure Of CO2, whereas the ignition probability of Al particles in CO2 is low but independent on pressure. Analysis of flame images and combustion parameters shows that the mechanism of Mg particle burning in CO2 corresponds to conventional models of vapor-phase diffusion-controlled combustion, whereas in the case. of Al exothermic processes on the particle surface or close to it play a leading part in the burning process.