Focal plane arrays is the core component of the uncooled infrared imaging system, based on the technical parameters of uncooled focal plane infrared detector produced by the French UILS UL01011. Its working wavelength is 8~14 μm, the temperature sensor range is －20℃0℃. To expand its sensing range, the glass attenuation is installed before the uncooled infrared absorption slide. By calculating the experimental data of the different glass attenuation, the temperature range under different conditions is obtained, so as to improve its measurementrange.