Abstract: For the research on high temperature real gas effects of high-speed flows, numerical simulation was applied to study the surface recombination effects on the plasma sheath and electromagnetic parameters of the typical reentry body by solving the 3D Navier-Stokes(N-S) equations considering chemical non-equilibrium. The results show that, (1) the plasma density under full catalytic wall condition conforms with the variation trend of flight test results; (2) the dissociated atoms recombine on the full catalytic wall, resulting in the more compressible gas, the shorter shock off-body distance, the higher temperature and lower plasma density; (3) along the stagnation line, the collision frequency under the full-catalytic wall condition near the shock wave is smaller than that under the non-catalytic wall condition; (4) for the relative dielectric constant, the real part of the relative dielectric constant under the full-catalytic wall condition is bigger than that under the non-catalytic wall condition, while the imaginary part under the full-catalytic wall condition is smaller than that under the non-catalytic wall condition; (5)the influence of surface recombination on the conductivity of the plasma sheath is consistent with that on the relative dielectric constant.