An Indium Arsenic Antimony (InAsSb) thick film single crystal grown by new technology was presented. With this material, a highly sensitive uncooled photoconductive detector was made by using the same process as that of room temperature InSb detectors. The photoelectric properties and spectral responsivity of the detector were measured and compared with those of the room temperature InSb detector, the cooled InSb detector and the PbSe detector. The obtained data provided a reliable basis for the wider application of InAsSb detectors operating in the mid and long infrared waveband (5-12 μm).