The invention discloses a matching device and matching method for an ultrasonic power supply. The matching device for the ultrasonic power supply comprises an ultrasonic 
signal generator, a drive isolation circuit, an ultrasonic power amplification circuit, a matching 
transformer, a tuning 
inductor, an ultrasonic 
transducer, a 
voltage sampling circuit, a current sampling circuit, a filtering and shaping circuit, a phase 
discriminator, an A / D converter, a single-
chip microcomputer and a stepping motor. The output end of the matching 
transformer is connected with the tuning 
inductor; the output end of the tuning 
inductor is connected with the ultrasonic 
transducer; the 
voltage sampling circuit is used for collecting real-time working 
voltage signals at the two ends of a unit formed by the tuning inductor and the ultrasonic 
transducer, and transmitting the real-time working voltage signals to the phase 
discriminator. According to the matching device and matching method for the ultrasonic power supply, static 
impedance matching and 
dynamic impedance matching can be achieved, the matching 
inductance value can be tracked and adjusted through the 
phase difference of working currents and working voltages of the ultrasonic transducer, it can be ensured that the ultrasonic transducer always works at a 
resonance point, the maximum useful 
power output of the ultrasonic transducer can be achieved, in addition, the adjusting response speed is high, and accuracy is high.