The ultrasonic tool head is an ultrasonic radiating head shaped like a torus body or similar to a torus body, and the ultrasonic tool head has at least one first torus surface that radiates ultrasonic waves by bending vibration mode. The utility model uses a radiation surface with curvature to replace a single plane radiation surface, greatly increasing the radiation area of the tool head; At the same time, the radial surface of circular ring or similar circular ring tool head is similar to circular ring radial radiation, so the uniformity of sound field in liquid or gas is better; Thirdly, the radiation surface adopts bending vibration mode, which changes the transmission direction of vibration, makes the radiation sound intensity more uniform and improves the flexibility of tool head. It can be applied to some ultrasonic welding with a similar circular surface section, and can also be used as a kind of horn.