The combustion process of hydrocarbon fuel will produce a lot of carbon smoke. C₂H₂, as an important precursor of carbon smoke products, has an important effect on carbon smoke generation, so it is of great significance to achieve direct detection of C₂H₂ in combustion environment. In this work, a tunable diode laser absorption spectroscopy system was established to detect C₂H₂ gas absorption spectra at different temperatures and pressures by simulating combustion environment in a high temperature and high pressure gas pool. Specifically, taking a tunable semiconductor laser with a central wavelength of 1542 nm as the light source, the absorption line extinction signals of acetylene at 6489.074 cm^-1 and6490.020 cm^-1 were obtained using the scanning wavelength direct absorption method, thereby achieving simultaneous measurement of C₂H₂ concentration and temperature. The experimental results show that, in the pressure range of 1.01 × 10⁵–5.05 × 10⁵ Pa and temperature range of 500–1100 K, the relative average standard deviations of gas volume concentration and gas temperature measurement are 4.59% and 2.47% respectively, which are in high agreement with the reference values. It proves that the developed system in this work can provide assistance for simultaneous measurement of gas concentration and temperature under high temperature and high pressures.