A laser direct imaging system includes a stage, a laser device and an oxygen-reducing device. The stage is subjected to an atmospheric pressure. The laser device is configured to provide a laser beam to scan across the substrate. The oxygen-reducing device operates simultaneously with the laser device for outputting an inert gas only to a specific area where the laser beam is being aimed such that any portion of the substrate, if enters the specific area, will be exposed to the laser beam under a low-oxygen environment.