A waveguide rod for an ultrasonic scalpel having a relatively desirable amplitude and frequency comprises a proximal gain structure, a distal gain structure, an intermediate structure, and a frequency adjustment structure. The proximal gain structure and the intermediate structure are connected in a position near an antinode of longitudinal vibration of the waveguide rod through a proximal side gain step. The distal gain structure and the intermediate structure are connected in a position near an antinode of the longitudinal vibration of the waveguide rod through a distal side gain step. The intermediate structure comprises N (N >； 0, and N is an integer) gain holding structures that are connected end-to-end in a position near an antinode of the longitudinal vibration of the waveguide rod through an intermediate gain step. X (X >； 0, and X is an integer) frequency adjustment structures exist on the gain holding structure. The waveguide rod provides an ultrasonic scalpel with a relatively large blade amplitude and also enables the ultrasonic scalpel to work at a stable and suitable vibration frequency, so that the ultrasonic scalpel can cut human tissue efficiently.
