Abstract: With its broadband characteristic and the ease of manufacturing, transmission line transformers have been widely used in communication. However, few articles have been published to mention the fact that impedance match between an ultrasonic transducer and the signal source can be achieved by using a transmission line transformer. Analysis is given in this article on how a transmission line transformer can realize broadband impedance match. Through a simple equivalent circuit it is illustrated that distributed capacitance along the transmission line can be utilized, turning an adverse factor in the transmission of high-frequency energy to an advantage. As a result, transmission of energy over a broad frequency band is realized. As an example, design of an impedance match transformer of an ultrasonic transducer working in the frequency range of 500kHz-2MHz is described. The characteristic impedance, wire length, magnetic core, specifications of wire, and winding turns are determined.