The invention belongs to the technical field of automobile explosion proofing and fire prevention, and particularly relates to an automatic fire extinguishing system for the explosion-proof vehicles.The system comprises a fire extinguishing tank, a pressure switch, a fire extinguishing pipeline, nozzles, a trigger pipeline, and fire source detectors, wherein the pressure switch is arranged at theoutlet of the fire extinguishing tank; the fire extinguishing pipeline is arranged at the back of the pressure switch; the nozzles are installed on the fire extinguishing pipeline at intervals; the trigger pipeline is arranged at the inlet of the fire extinguishing tank; and the fire source detectors are installed on the trigger pipeline at intervals. The location and the number of the nozzles and fire source detectors are arranged according to the position and the volume of an engine and an electrical system of the explosion-proof vehicles. According to the automatic fire extinguishing system for the explosion-proof vehicles, by using a pneumatic mode to control, no external power supply is needed; and after installation, the pipelines have no pressure inside in the normal state of the system, so that the structure of the automatic fire exteinguishing system is simplified.