Abstract: The avalanche photodiode (APD) is a photosensitive component commonly used in devices employed in the field of laser detection. In this study, a field-effect transistor quenching circuit is designed for a Geiger-mode (Gm)-avalanche photodiode for detecting avalanche effects. First, a circuit model of a Gm-APD was established based on the characteristics of a traditional Gm-APD device. Second, based on this model, afield-effect transistor quenching circuit was simulated to confirm the rapid quenching of the Gm-APD. Results indicated that the field-effect transistor quenching circuit in this study exhibited a high quenching speed, a short dead time, and improved performance. The quenching and death times were 21.026 and 16.5 ns, respectively, which meet the application requirements of laser ranging imaging.