The invention discloses an ultrasonic/megasonic cleaning device with a dynamically changed frequency. The ultrasonic/megasonic cleaning device comprises a body and an ultrasonic/megasonic frequency control unit, wherein an ultrasonic/megasonic generation mechanism and a bottom quartz component are arranged in the body; the ultrasonic/megasonic generation mechanism is equipped with a piezoelectric material which is connected with a signal source outside the body; the bottom quartz component is equipped with a quartz microresonator array which extends out from an opening in the lower end surface of the body; the ultrasonic/megasonic frequency control unit is connected between the signal source and the piezoelectric material; and the quartz microresonator array can be used for selectively removing ultrasonic/megasonic energy in the transmission direction non-perpendicular to the surface direction of a wafer, and the ultrasonic/megasonic frequency control unit is used for changing the frequency of an electric signal output by the signal source, so that the ultrasonic/megasonic vibration frequency generated by the piezoelectric material can be dynamically changed, and non-destructive cleaning for a circular wafer can be realized.