The electrical and optical properties of narrow gap semiconductor mercury cadmium telluride materials directly affect the performance of infrared detectors. Doping is an effective means to improve the material properties, so it is very important to study the doping of mercury cadmium telluride materials. A step-scanning Fourier transform infrared modulated photoluminescence (FTIR-PL) spectrometer was used to measure the temperature change of In-doped mercury cadmium telluride in different annealing conditions. The signal-to-noise ratio (SNR) during the experiment was reduced and a better spectra was obtained. Based on the results, combining the Hall data, the change of energy level position caused by temperature change was analyzed as well as the change of luminescent peak intensity and position of mercury cadmium telluride materials after different annealing conditions.