This paper briefly discusses the classification of eavesdropping technology and the principle of infrared thermal imaging, analyzes the feasibility of applying infrared thermal imaging technology in the field of anti-eavesdropping, and emphatically introduces a design scheme of the anti-eavesdropping equipment based on cooled infrared focal plane detector. The scheme has certain technical advantages and good detection effect for some eavesdropping devices. The design of this scheme is based on users and usage scenarios, and focuses on man-machine adaptability, so it has a certain market prospect.