Abstract: Thrust generated by ionic wind has the advantages of no mechanical rotating parts, low power consumption and low noise, and has important application potential in stratospheric airships and solar planes. The wire-cylinder electrode corona discharge device was used to generate ionic wind. The thrust and the thrust-to-power ratio generated by the ionic wind thruster were measured under different operating conditions, including the air pressure, the applied voltage, and the electrode gap distance. The results show that the decrease in air pressure will lead to a reduction in the thrust-to-power ratio. For example, when the electrode gap is 2.0 cm, the maximum thrust-to-power ratio is reduced from 17.70 mN/W at 1.0 atm to 0.24 mN/W at 0.02 atm. The loss of the thrust-to-power ratio can be compensated by increasing the electrode gap. When the electrode gap is increased from 2.0 cm to 14 cm at the pressure of 0.02 atm, the thrust-to-power ratio rises from 0.24 mN/W to 0.70 mN/W. By optimizing the structure of the ionic wind thruster and selecting the appropriate electrode gap distance, the ionic wind thrust has more applications in low-pressure environments.