Abstract <p>The plasma gas kinetic temperature in the reaction of synthesis of titanium dioxide (TiO₂) microparticles with copper (Cu) nanoparticles deposited on them is estimated from the radiation of a titanium oxide (TiO) molecule. The synthesis reactions have been initiated by microwave radiation of a powerful gyrotron in a mixture of titanium dioxide and copper powders. As a result, materials are obtained that include micro-sized titanium dioxide particles of rounded shape ranging in size from 10 to 200 μm with copper nanoparticles deposited on their surface. The copper concentration in the powder mixtures varied from 0.1&#xa0;to 20 wt %. The microwave breakdown in the mixtures is provided by the use of a steel initiator. The gas kinetic temperature is estimated from the radiation spectrum of the TiO molecule γ-system in the range from 700 to 720 nm. The bands in this range are caused by electron transitions between the А³Φ–Х³Δ molecular states. It is shown that the synthesis is carried out at the same gas kinetic temperatures of 5500 ± 500 K, which do not depend on the copper content in the powder mixture.</p>