Abstract: In order to explore the temperature measuring ability under the high-pressure condition and in a confined space, the filtered Rayleigh scattering technique is developed based on the iodine molecular ultrafine absorption. The filtered Rayleigh scattering temperature measuring apparatus, consisted of the seed laser, the Nd:YAG laser, the iodine molecule filter and the ICCD camera, is designed. And the iodine filter is used to remove the stray light interference from the soot and wall reflection. Moreover, this apparatus is applied on a high-pressure gas combustor (0.1~0.5MPa) to obtain the temperature distribution above the flat burner quantitatively. The results show that the relative uncertainty in the single-shot imaging is estimated to be about 15%. And a better than 10% agreement to the single point measurement is achieved by the thermocouple. Therefore, the filtered Rayleigh scattering technique is expected to be applied in the temperature measurement of the engine combustion.