A new kind of non-contact temperature measurement technique based on tunable diode laser absorption spectroscopy (TDLAS) was investigated. Temperature measurement principle and modulation absorption spectroscopy were introduced, and the influence of modulation amplitude on gas temperature measurement was analyzed. A pair of oxygen absorption lines, 13163.78 cm-1 and 13164.18 cm-1, were optimally selected. Oxygen temperature and concentration were measured simultaneously with a high-temperature experimental setup. By analysis of second-harmonic signals, the collisional width and the temperature index of the spectral line 13164.18 cm-1 in the temperature range of 823～1323 K were acquired. Experimental results show that the linear error and maximum fluctuation of temperature measurement are 0.65% and ±15 K, respectively within the temperature range of 823～1323 K.