Abstract: In this paper, the pyroelectric infrared detector of experimental device is designed, and the structure and working principle of pyroelectric infrared sensor are introduced.The infrared radiation of human body is changed into a faint voltage signal by the pyroelectric infrared sensor.The voltage signal is magnified by a band pass filter, and a high electrical level is exported from the window comparison circuit, which drives the diode emitting.The experimental contents contain the infrared signal processing and response to the distance characteristic experiments.The circuit principle and experimental method were introduced and analyzed.By using this experimental device, some actual application circuits, such as pyroelectric infrared alarm and infrared automatic switch were developed.This experimental device was applied to infrared detection experiment and innovation design for the students in the departments of electronics science and technology, and controlling technology and equipment of Henan University.