The present disclosure provides an ultrasonic drive and driving method configured for driving an ultrasonic tool. The ultrasonic drive includes a switch module, a sensing element and a control element. The sensing element senses the voltage and current of the ultrasonic tool and generates a sensing signal accordingly. The control element receives the sensing signal and outputs a control signal. The switch module outputs an ultrasonic signal according to the control signal for controlling the vibration of the ultrasonic tool. When the ultrasonic drive operates a frequency sweep function, the control element determines an operating interval and an operating frequency of the ultrasonic signal. When the ultrasonic drive operates a frequency following function, the control element adjusts the operating frequency according to the sensing signal for keeping the impedance of the ultrasonic tool consistent.