Laser active detection is a technology to detect and identify enemy reconnaissance equipment by using the "cat′s eye effect" of optical system.Its core technology is to pinpoint the location of enemy optical detector,so as to implement interference or other measures to the detector.The basic model of laser transmission in laser active detection is set up,and the influence of several conditions,such as atmospheric attenuation,defocusing amount and incident angle,on laser active detection is discussed.Based on the photoelectric echo image of laser active detection,as well as the laser transmission characteristics in actual detection process,the three criteria of echo power,target size and target shape are creatively proposed and combined with the traditional target detection algorithm,and the accurate identification and positioning of enemy detection equipment is realized.The testing via examples verifies that this algorithm has better recognition ability than the traditional algorithm does,and has strong universality and certain value in actual combat applications.