In the practical high-temperature gas detection case, the measured results of the gas spectral line parameters are often affected by temperature changes. Sometimes, it is even difficult to achieve real-time online measurement.Therefore, this paper aims to design and process a new high-temperature sample cell to simulate a high-temperature environment and build a tunable diode laser absorption spectrum measurement system to detect the spectrums of the target gas in a high-temperature environment. In this way, the accurate detection of spectral line parameters can be achieved.In the design of a high-temperature sample cell, Comsol was used to simulate and analyze the solid thermal conductivity of various materials to determine the optimal processing materials and size. The results show that good properties of the high-temperature sample cell are obtained. It can work in the temperature range of 300~1 000 K and the pressure range of -0.1～10 atm. The maximum temperature deviation of the sample cell at 1 000 K is 20 K. The measured leakage rates at 300 and 1 000 K are 5 and 60 Pa·min-1, respectively.This paper uses a distributed feedback (DFB) semiconductor laser with a center wavelength of 1 573 nm as the light source to measure the partial high-temperature spectrums of CO molecules with relatively accurate parameters in the HITRAN2016 database. The comparison between the spectral line parameters obtained from the inversion and those in the HITRAN database indicates that the error is within 5%. The good performance of the designed high-temperature sample cell was proved, which can help in the measurement of gas spectral line parameters in high-temperature environments.