Rh-based catalysts are widely used in CO hydrogenation to ethanol. In this work, Rh/TiO2 catalysts were prepared by glow discharge plasma. Rhodium salt was reduced by electrons in an electric field at room temperature. Oxygen vacancies and Ti3+ were produced on the surface of Rh/TiO2 by plasma. The defects promoted the synergistic effect of Rh and TiO2 through the enhanced interaction between active metal and supporter. Ti3+ is beneficial for the adsorption of intermediate formyl group. In situ IR revealed that the bridged and linear adsorption mechanisms of CO can promote the formation of ethanol intermediates. Rh/TiO2 catalysts by plasma exhibited a superior space-time yield of 0.106 gMeOH·gcat–1 h–1, at 260 °C and 3 MPa, which was approximately 1.8 times that by traditional hydrogen reduction.