As the single electron transfer of CO2 to CO2− ions is the critical step in the CO2 activation, it is very important to develop appropriate strategies to construct efficient catalytic systems. Herein, we constructed a coupled catalytic system consisting of mechanical-energy-driven triboelectric plasma and indium oxide rich in oxygen vacancies to achieve CO2 reduction to CO at room temperature and atmospheric pressure. At the discharge distance of 0.6 mm, the indium oxide with more oxygen vacancies exhibited an optimal catalytic activity of 0.20 mmol·g−1·h−1 for CO evolution rate, and the conversion efficiency from electrical to chemical energy was 10.8 %. Electron paramagnetic resonance experiments showed that a large amount of CO2− ions were generated in the triboelectric plasma. The introduction of oxygen vacancies could increase the density of states near the Fermi level of indium oxide catalysts, stabilize highly active CO2− ions, and reduce the energy barrier of CO2− decomposition.