Abstract: The production of hydrogen-rich gas by plasma reforming of DME was conducted in a self-made three-cavity reformer at atmospheric pressure and ambient temperature. The effects of reformer structure parameters, electrode material, heat transfer characteristic, and operation parameters on the gas composition and hydrogen yield were investigated. The results indicated that with the increase of pulse duty ratio and arc frequency, the yield of hydrogen increases first and reaches a maximum when the pulse duty ratio and arc frequency are 80% and 170Hz, respectively. The yield of hydrogen increases with the increase of anode diameter and discharge cavity number, but decreases with the increase of anodic heat transfer characteristic. The optimal air/DME ratio is 3.5 to get the highest hydrogen yield. Hydrogen yield and hydrogen concentration in the product can be enhanced by using iridium anodes, cuprum cathodes and reasonable radius of cavities.