Abstract: An atmospheric-pressure microwave plasma torch(APMPT) is employed to drive Boudouard reaction to convert CO₂ into CO for the purpose of resource utilization. The process of Boudouard reaction driven by APMPT is diagnosed by optical emission spectroscopy(OES) and the chemiluminescence occurrence is observed experimentally. The variation of CO concentration is measured with respect to the microwave power when the graphite rod is placed in the downstream of the afterglow of CO₂ APMPT by means of gas chromatograph(GC). Furthermore, a hollow graphite rod is proposed, thereby the conversion rate is enhanced, and the variation of conversion with the microwave power, gas flow rate, geometric sizes of rod, and composition of working gas is investigated. Furthermore, the conversion effects by Boudouard reaction with use of various carbon materials are compared and the discussion of mechanism is delivered. The experimental results indicate that the Boudouard reaction occurring on the surface of graphite rod plays the pivotal role in CO₂ conversion into CO, and the concentration of the generated CO increases with diameter of the hollow graphite rod; meanwhile, the addition of Ar or N₂ into carrier gas CO₂, respectively, will improve the CO concentration.