In order to abate the effects from the background disturbance in the system of laser proximity fuze, such as the smoke, mist, rains, clouds, snow and other artificial disturbances, a device based on the "dual range gate" techniques is designed. It can eliminate the natural interferences and disturbance as the rounds with pulse laser proximity fuze flights in the atmosphere. And moreover its detecting ranges reach 10 meters. The device improves greatly the anti-disturbance performance of the pulse laser proximity sensors.