Abstract: In order to investigate the properties of electron beam plasma in high velocity flow, a multi-stage numerical model including the Monte Carlo model, multi-fluid plasma model and CFD model is established. In the near-sound-speed flow, the characteristics of electron beam air plasma are studied in detail. The results indicate that the energy deposition of the electron beam is nonuniform in space and the flow fields are distinct in subsonic and supersonic flow. In the subsonic flow, the density of boundary layer in the downstream decreases; but in the supersonic flow, a weak shockwave is induced by the injected beam. The plasma density decreases and the significant plasma transportation is observed in the high velocity flow, thus the plasma is transported to the downstream. The effect of the velocity magnitude on the plasma distribution is small in the near-sound-speed flow. However, the injection angle of beam influences the plasma density and distribution significantly.