The invention relates to a traffic violation snapshotting system and a traffic violation snapshotting method. A device comprises an L-shaped metal rod piece, a passive infrared sensor, a sensor signal amplification and shaping circuit, a camera, an image collector, a photographing light supplement lamp, a synchronous light supplement controller, a signal lamp detection circuit, a snapshotting system controller, a warning lamp, a voice output device and a video output device. The method detects non-motorized vehicles and pedestrians by adopting the passive infrared sensor, conducts automatic control, snapshotting and evidence obtaining on a behavioral course of a field violated person to serve as off line data processing, is applicable to the field of road traffic, obtains images and videos of the non-motorized vehicles violating the traffic and violation behaviors of the pedestrians in real time, is applicable to the snapshotting and the evidence obtaining of the violation behaviors of the non-motorized vehicles and the pedestrians on a road at present, has an acousto-optic warning function, can prompt the violated non-motorized vehicles and the pedestrians, can store the videos and the images, and facilitates later data statistics, analysis and calling.