Based on tunable diode laser absorption spectroscopy technique, the measurement method of CO2 temperature and concentration in high temperature environment is studied. The CO2 absorption line near 4996 cm -1 is selected as the target detection line to measure CO2 temperature and concentration in high temperature environment. The CO2 concentration and temperature of CO2/N2 mixed gas in the gas absorption cell at different temperatures (873-1273 K) and different CO2 volume fraction (4%-10%) are measured. The results show that, compared with the setting values, the average deviation and peak deviation of the measured temperature are 2.07% and 3.49%, respectively. The average deviation and peak deviation of the measured concentration are 2.25% and 4.75%, respectively. The results indicate that the proposed method is accurate, and it provides references for CO2 detection in the high temperature environment.