In the present paper the thermal infrared spectral variation of quartz sandstone under uniaxial compression was detected by a spectroradiometer to study the sensitively responding waveband of infrared radiation excited by the pressure. The experimental result shows that the infrared spectrum varies with the load, and the variation feature is different in different wavebands. The infrared radiation intensity increases with the increase in the load within the waveband 8.0～11.5 μm (specially in 8.6～9.1 μm), and there is a quadratic correlation between them, meanwhile the signal-to-noise ratio of spectrum radiation is also higher in the waveband. But in other wavebands the correlation is worse and the signal-to-noise is also lower. This indicates that the waveband 8.0～11.5 μm is the sensitive waveband of infrared radiation to the pressure, and it is also the superior waveband for infrared remote sensing monitoring the stress and catastrophe of rock. The optimum waveband is 8.6～9.1 μm.