Provided is an ultrasonic transducer and a preparation method thereof. The ultrasonic transducer includes a housing. A piezoelectric layer is disposed in the housing and includes at least two piezoelectric array elements. A frequency interval between the piezoelectric array elements is 50 kHz to 1.2 MHz. An acoustic lens is disposed at a front end of the piezoelectric layer and is used for ensuring that the piezoelectric array elements having different frequencies have a common focus.
