During spacecraft reentry into Earth’s atmosphere, the temperature of the high-speed air at the front of the spacecraft can reach over 10 000 K, leading to changes in the aerodynamic performance of the spacecraft. Radiative heating is one of the main sources of surface heat transfer for spacecraft, and measuring the radiation spectra of air under high-speed shock waves is crucial for studying radiation effects and dynamic behavior during the flight of hypersonic vehicles. There is still a lack of measurement data for high-temperature air radiation spectra, and a large amount of experimental data is required to improve and optimize computational models. This paper uses a hydrogen-oxygen detonation shock tubecombined with a transient spectroscopic measurement system to obtain the radiation spectra of high-temperature air in the ultraviolet-visible region at velocities ranging from 3 259～8 218 m·s^-1. The identification and simulation of typical high-temperature air radiation spectra characteristic spectra were carried out. The simulation results were in good agreement with the experimental results, validating the accuracy and reliability of the spectral identification. The impact of shock wave velocity on the radiation characteristics of high-temperature air was also analyzed, and the dynamic behavior of characteristic spectra was analyzed. The results showed that characteristic spectra mainly exist in the 225~675 nm wavelength range and the region with wavelengths below 500 nm. Different characteristic spectra were observed in the radiation spectra at different velocities. With increasing shock wave velocity, OH(A-X), NO(γ, ε, δ), NH(A-X), N₂(C-B), , and Hα spectral lines appeared successively. The relative intensities of the characteristic spectra vary with shock wave velocity. Finally, the relaxation time of post-shock air excitation was determined based on the time-varying curve of radiation intensity. The relaxation time gradually shortened with increasing velocity and exhibited an exponential relationship with velocity. This study provides experimental data and references for spacecraft thermal protection design and the validation and optimization of computational models for hypersonic reentry into the atmosphere.