This paper studied the variation of the stress-related thermal infrared spectrum of the rock under pressure. The thermal infrared spectrum radiation from two kinds of granites under uniaxial compression at room temperature was monitored with a spectroradiometer (8～14 μm). The experimental results show that the infrared radiance (amount of increase) of rock varies linearly with the stress. The stress sensitive waveband is determined by the mineral component and structures of the rock. The correlation coefficient between infrared radiance and load was analyzed comprehensively, so was the ratio of maximal variation to standard deviation. The results show that sensitive waveband to stress is in the range of 8.4～10.6μm for rich-feldspar porphyritic granite with central band at 8.75 μm; while for rich-plagioclase and equigranular granite, the sensitive waveband to stress is 8.2～11.7 μm, and centered at 10.25 μm. These wavebands can be used as reference for monitoring of the stress and catastrophe of the rock with infrared remote sensing.