By using a clever circuit structure and analog signal processing method, a circuit was designed to extract weak pulse signal from clutter. Firstly, the input signal was saturated and amplified, and then filtered in two stages. The output signal of the primary filter was compared with the output signal of the secondary filter in the comparator, so as to generate the pulse signal, and the output pulse width was adjustable. The structure of the circuit was simple and the use of fewer components was convenient for miniaturization. The circuit was processed by thick film technology. The results showed that the pulse width error of the circuit was 1.0% and the output pulse delay time was 51 ns. The circuit had the characteristics of strong ability to detect weak signal, small change of pulse width, strong anti-interference, small size, low power consumption and good consistency, and it was suitable for mass production.