In order to analyze the performance of coherent laser fuze under cloud and fog interference, the detection model of coherent laser fuze in cloud and fog was created based on Mie scattering theory and Monte Carlo method. Through simulation, the echoes of coherent laser fuze were obtained in various scenes. The time-domain and frequency-domain characteristics of echoes were analyzed, as well as the influence of cloud and fog visibility, detection position, and detection angle on echoes. The results show that the coherent laser fuze can accurately identify the target by using the frequency-domain characteristics, and is not easily affected by factors such as cloud and fog visibility, detection position, and detection angle. The results demonstrate the excellent detection performance of coherent laser fuze in cloud and fog.