To reduce the personnel and material loss caused by fire, we propose the automatic fire extinguishing system based on the ignition point tracking using the flame detecter. This automatic fire extinguishing system is composed of the flame detecting system and the fire extinguishing system based on the water cannon. We study the method for the ignition point tracking and the automatic fire extinguishing using the water cannon and the flame detecter. The flame detecting system for the early fire detection and the ignition point tracking has to be satisfied the requirement of the detecting range and the flame detection time. So we study the signal process algorithm for an improvement of the flame detecting system.