Abstract: A boosting-inverter power conditioning unit is designed,in which high voltage pulse ignition arc used as start-up circuit and peak current closed-loop feedback control used as the control circuit.High ignition ability,plasma arc stability and excellent dynamic response quality are demonstrated by vacuum operation experiment of the arcjet thruster.According to national standard GB9254—2008,a radiation continuous emission test was done to the power conditioning unit,and the test results were satisfactory.