Abstract: In order to further enhance excitation efficiency of the electromagnetic ultrasonic excitation source,and to improve the work efficiency of the electromagnetic ultrasonic transducer,a Class-DE power amplifier based on the radio frequency(RF) technology was presented by using isolated power supply method.The high side metal-oxide-semiconductor field effect transistor(MOSFET) "floating" problem was effectively solved.By analyzing the MOSFET switch working state and control characteristic,the basic process of MOSFET switch was established,thus a MOSFET driver circuit design method was built.Through selection of key components design and algorithm research,the DE class driver circuit of power amplifier was conducted.Experiments show that the output signal voltage amplitude of the MOSFET drive circuit is 13.4 V,the duty ratio is 50%,the working frequency is 1 MHz,the output signal is stable,the MOSFET reliable drive is obtained,and practical application is satisfied.