The invention provides an ultrasound knife exciting device and an exciting method, and aims to solve the technical problems that a traditional ultrasound knife exciting device adopts more separation elements, electric signals among the elements have poor transmission accuracy, and separation elements have large performance drift after long-time using and cannot generate stable and high-performance sinusoidal signals or generate sinusoidal signals with stable frequency and uniform amplitude to excite the ultrasound knife. The device comprises a main processor, a main power supply, a fixed reference power supply, a user keyboard, an LCD display module, an FPGA unit, a digital-to-analogue conversion unit, an analogue-to-digital conversion unit I, an analogue-to-digital conversion unit II, an adjustable switch power supply, an adjustable reference power supply, a clock unit, an amplification circuit, a signal regulation circuit, a voltage monitor module, a current monitor module and a signal output end. The ultrasound knife exciting device and the exciting method can be widely applied to surgical operation devices.