The invention relates to an underwater target tracking method based on a forward-looking sonar image, and the method can accurately track the position of an underwater target, and includes carrying out the real-time quick detection of the underwater target, and completing the installation and debugging of a GPS, an attitude sensor, a holder, a PC and forward-looking sonar equipment; controlling the pan-tilt to move in a detection range through the PC, and giving a tracking target; acquiring information data; recovering the sonar information into a gray level image of the sonar according to theintensity of the forward-looking sonar callback signal; preprocessing the images, extracting two groups of feature points to obtain two groups of feature point sets, matching the feature point sets to separate correct matching from error matching, and calculating a target image, transformation coordinates and a transformation matrix; and performing repeated matching and repeated transformation toobtain a transformation matrix of the current target position, thereby realizing underwater target tracking based on forward-looking sonar image matching. According to the underwater target trackingmethod, the position of the target is accurately tracked, the detection speed is high, and the method has the characteristic of real-time performance.