The infrared thermometer collects the thermal radiation of the measured target by using the infrared sensor, converts the optical signal collected by the infrared sensor into an electrical signal through the conversion circuit, and then sends the electrical signal to the single chip microcomputer after processing through the amplification circuit, a / D conversion and other unit circuits. At last, the single chip microcomputer analyzes and processes the electrical signal with data information, and converts the electrical signal into the temperature value display output corresponding to the size of the.The problems to be solved are: non-contact measurement of body temperature signal, amplification of weak voltage signal, ambient temperature compensation of sensor and so on. Among them, infrared thermoluminescence sensor is selected for temperature measurement, voltage amplification, analog-to-digital conversion, system control and data processing are realized by single chip microcomputer, and displayed by driving common cathode nixie tube. The infrared thermometer is composed of optical system, photoelectric detector, signal amplifier, signal processing, display output, alarm circuit and so on.