An ultrasonic surgical instrument with a detachable cannula component, comprising a cannula component and an instrument body, wherein the instrument body comprises a scalpel bar for producing an ultrasonic cutting effect; and the cannula component is mounted on the instrument body or dismounted from the instrument body by a detachable structure along the longitudinal axis of the scalpel bar; and the detachable structure comprises multiple first detachable elements; and the instrument body is fixedly connected with the cannula component by at least one of the first detachable elements; wherein the first detachable structure comprises a first boss, a first limiting slot, a stopper and an elastic element, wherein the first boss is located on the cannula component, and the first limiting slot and the stopper and the elastic element are located on the instrument body; or wherein the first boss is located on the instrument body, and the first limiting slot and the stopper and the elastic element are located on the cannula component; and wherein: the first limiting slot comprises a first slot parallel to a longitudinal axis of the scalpel bar and a second slot circumferential to the longitudinal axis of the scalpel bar; the first boss is capable of sliding along the direction of the longitudinal axis of the scalpel bar in the first slot of the first limiting slot, and also is capable of sliding rotationally about the longitudinal axis of the scalpel bar in the second slot of the first limiting slot; the stopper is configured to be capable of sliding along the direction of the longitudinal axis of the scalpel bar in the first slot of the first limiting slot, while incapable of entering the second slot of the first limiting slot; and wherein: the stopper is connected with the elastic element, and the elastic element is capable of providing an elastic force along the direction of the first slot of the first limiting slot, and the stopper is located at an intersected point of a first slot structure and a second slot structure of the first limiting slot in an initial state under the action of an elastic force of the elastic element. the first limiting slot comprises a first slot parallel to a longitudinal axis of the scalpel bar and a second slot circumferential to the longitudinal axis of the scalpel bar; the first boss is capable of sliding along the direction of the longitudinal axis of the scalpel bar in the first slot of the first limiting slot, and also is capable of sliding rotationally about the longitudinal axis of the scalpel bar in the second slot of the first limiting slot; the stopper is configured to be capable of sliding along the direction of the longitudinal axis of the scalpel bar in the first slot of the first limiting slot, while incapable of entering the second slot of the first limiting slot; and wherein: the stopper is connected with the elastic element, and the elastic element is capable of providing an elastic force along the direction of the first slot of the first limiting slot, and the stopper is located at an intersected point of a first slot structure and a second slot structure of the first limiting slot in an initial state under the action of an elastic force of the elastic element.