When vehicles re-enter the Earth's atmosphere at hyper-velocity, gas radiative heat will increase dramatically, even larger than convective heat. To reduce the design margin of thermal protection system, radiative heat must be considered and predicted accurately. Firstly, experimental tests of absolute gas radiative intensity measurement have been conducted in a combustion driven shock tube to validate the computational models and methods. The absolute value of gas spectral emission radiation in the spectrum range of 330 to 370â...nm has been obtained for air at the velocity up to 8â...km/s. Secondly, Unsteady Navier-Stokes equations with thermo-chemical non-equilibrium models, narrow-band radiation model accounting for both electronic and vibrational-rotational transition, and radiation transfer equation have been respectively solved to get the flow parameters and spectral radiant intensity at corresponding test condition with high spectrum resolution. The comparison between experimental and computational results showed an excellent agreement. Finally, numerical simulations on an Apollo-like re-entry vehicle FIRE II have been implemented. The results showed that radiative heating rate integrated in solid angle space and spectral interval were approximately the same for two catalytic wall conditions. Radiative heating rate decreased slowly and monotonously along the radial direction, while convective heat rose up again on the shoulder. The total heating rate of non-catalytic and super-catalytic wall covered the flight data. © 2019 Author(s).