Abstract: The semi-active laser seeker has been widely used in weapon guidance systems due to its miniaturization, low cost, and high precision. Concerning the issues of low signal-to-noise ratio and weak detection ability of weak laser echo signals, this paper analyzed the relevant factors influencing weak echo signals. It was proposed to suppress background noise from the perspective of the optical system, and optimize the indicators of the spot ellipticity and uniformity. By using high-speed direct sampling method for multifeature recognition and judgment, achiving feature extraction of weak signal complete waveform, improving signal-noise ratio.The results of laser spot quality and high-speed direct sampling experiments indicated that the ellipticity of the spot is about 95%, and the uniformity is 80%, the signal-noise ratio is greater than 10 dB, the detection limited distance is greater than 6 km. This study meets the needs of laser detection in terms of long-range terminal guidance, antiinterference, and has certain engineering application reference value.