In the industrial heating furnace，due to the influence of high temperature environment, the general detector cannot measure the real temperature of the workpiece .Aiming at the temperature detection of industrial heating furnace, a real-time temperature measurement system of polysilicon infrared detector is designed. The relationship between the detector output and the ambient temperature, as well as the photoelectric conversion performance were tested by blackbody furnace, the results show that the output decreases sharply when the working environment temperature exceeds 30℃, with the increase of target temperature, the dynamic range decreases. The design adds an attenuator in front of the detector and a protective cover with sandwich structure, the results show that the system effectively expands the dynamic range of the polysilicon infrared detector and ensures that the ambient temperature of the detector is within 30 ℃, The measurement accuracy reaches 0.85 ℃, which meets the industrial requirements, and solves the application of polysilicon infrared detector in industrial heating furnace.