To contribute to the development of more competitive combustors by the command of heat exchanges, the determination of temperature and concentration distributions of combustion products is required. Emission spectroscopy of gas species has been investigated for passive and nonintrusive measurements in combustion processes under severe conditions ( T> 2000 K and P> 10 bar). We have designed an experimental facility to study radiative properties of water vapor produced during combustion of a reactive H-2-air mixture for different initial conditions. The enclosure is efficient and dynamic pressures up to 80 bar were recorded with a good reproducibility. Emission measurements of H2O were performed in the 0.8 mum band using a high resolution spectrometer and a CCD detector. These spectra are compared to simulations with the HITEMP database. In the measurement spectral range, extrapolations from the spectroscopic database gave similar results to our initial experimental ones.