With the development of technology, modern warfare puts forward higher requirements for new weapons, and the development of hypersonic vehicles has attracted much attention. Infrared imaging equipment plays an important role in the terminal guidance field of hypersonic vehicles. Infrared imaging equipment is susceptible to interference from background radiation and thermal radiation from windows, and the background noise generated by the interference can easily cause imaging saturation. The imaging effects of mid- and long-wave thermal imagers were compared by experiments, high-temperature objects, the sun, clouds, sea surface, jamming bombs and rotating, high speed, high dynamics conditions. And the effects of spinel, yttrium oxide, zirconia and zinc sulfide materials' own thermal radiation on the imaging of medium and long wave thermal imaging instrument were compared, the relative attenuation rate of transmittance of windows at high temperature was obtained by testing. The comparative analysis show that the long wave thermal imager has advantages in anti-interference, and the zinc sulfide material has the advantages of low radiation, high transmittance and good pressure resistance. Mid- and long-wave comparison tests provide reference and support for the selection of working wavebands and window materials, and have reference value for the subsequent design and research of mid-long wavelength dual-band systems.