The characteristics of coaxial dielectric barrier discharge in atmospheric pressure air are studied by using a high frequency and high voltage AC power supply with adjustable voltage amplitude and frequency; After introducing the working principle of the dielectric barrier discharge device, the law of the load voltage and its frequency, discharge current, resonant current changing with the DC side voltage of the inverter under the natural resonant frequency and 1/3 natural resonant frequency of the AC side circuit of the power inverter is studied, and the characteristics of the load voltage and discharge current under the same DC side voltage of the inverter are compared The results show that before the initial discharge occurs, the DC side voltage of the inverter circuit of the power supply increases linearly, and the load voltage and discharge current increase accordingly, and the load property is always capacitive; After discharge, the load voltage is approximately constant, the discharge current increases approximately linearly, and the load property is resistance capacitance; In the positive and negative half cycle of the applied power supply voltage, the micro discharge current waveform is asymmetric, showing the characteristics of "glow like discharge" and "filiform discharge" respectively