The electro-optical observation, aiming and reconnaissance devices with cat-eye effect have been a huge threat in modern battlefield. In order to realize the effective detection of cat-eye targets, the principle of laser detecting cat-eye is analyzed. According to the influencing factors of cat-eye efficiency, the conclusion of the detection efficiency of cat-eye affected by cat-eye target, background and distance is given. Based on this, a digital time gain controller of laser detection system is designed, the flexible configuration of time gain control curve is realized, and the adaptability of laser detection system to different application environments is improved.