Abstract: The flow field,around the plasma synthetic jet at different flight-altitudes,was experimentally simulated with the lab-built test platform,comprising the pressure generator,plasma jet actuator,sensors and control units.The influence of the low atmospheric pressure on the plasma jet velocity was investigated.The results show that the low atmospheric pressure has a major impact.To be specific,as the pressure decreased(or the flight-altitude increased),the peak jet-velocity was increased,instead of being decreased;in 0~10,000 m range,the peak jet velocity linearly increased,at an increase-rate of about 15% to 25% for every 1,000 m height increase;at 10,000 m,the peak jet-velocity was two times as fast as that at the ground.As expected,the low atmospheric pressure little affected the performance and operation conditions of the plasma-jet actuator,including the loading voltage amplitude,frequency and duty cycle.