The accuracy of absorption spectral parameters is very important for the on-line measurement of combustion gas based on tunable diode laser absorption spectroscopy. In order to apply the spectroscopic parameters in infrared region in detecting the H2O concentration, it is necessary to validate these parameters experimentally, especially the Ar-broadening coefficient, which is crucial to elementary reaction in combustion and validation mechanism. By using a distributed feed back diode laser as light source and combining with spectral parameters measurement system, four spectral lines of H2O around 1.39 μm were collected. The line intensity, self-broadening and N2-broadening coefficient were obtained. The results agreed well with those in HITRAN database and literature. Moreover, the Ar-broadening coefficient was acquired systematically for the first time. By using current measured spectra parameters, the time-history of H2O concentration from H2/O2/Ar combustion behind high temperature reflected shock waves was obtained and corresponding combustion kinetic mechanisms were validated. The results in this work will provide reliable database for the measurement of H2O concentration from the combustion process of hydrocarbon fuels, as well as the validation of corresponding combustion kinetics research.