Abstract: In this paper, the main parameters of plasma flow field related to electromagnetic wave propagation are analyzed, including electron density, resonant frequency, body collision frequency, etc. Some simulations are carried out with the finite-difference time-domain(FDTD) method. The results show that the reflectivity of electromagnetic wave increases and the transmissivity decreases with the increase of resonant frequency from meter-wave bands to millimeter-wave bands in the typical case. The reflectivity decreases with the increase of collision frequency from meter-wave bands to centimeter-wave band, while the regularity of transmissivity is not significant. Above millimeter-wave band, the reflectivity and transmissivity of plasma flow field is not related to collision frequency. Its reflection is weak, and the transmission is dominant. When the target height is 30−50 km and the speed is higher than 5 000 m/s, the plasma flow field near stagnation point has a significant absorbing effect on electromagnetic waves at S band, C band, and X band, resulting black barrier or radar echo attenuation. The experiment of measuring electromagnetic characteristics of plasma flow field based on high enthalpy shock wave wind tunnel was carried out. The C and X-band RCS data and electron density data of plasma flow field were obtained, and the correctness of simulation results was verified by the experimental data.