AbstractAn LiNbO3single crystal has large electromechanical coupling efficiency, and its elastic loss is small. Using the elastic energy trapping phenomenon of an LiNbO3single crystal, a piezoelectric transformer can be formed using a width‐shear mode. To reduce the internal loss, a high‐order mode of width vibration is used and multiple pairs of interdigital electrodes formed on the top and bottom surfaces of a piezoelectric substrate are used for both input and output.To analyze the performance of a piezoelectric transformer with interdigital electrodes, Mason's equivalent circuit is used. Finally, the relationship between the designed parameter by the new equivalent circuit and the characteristic of a piezoelectric transformer is investigated to compare the theoretical and experimental results. In particular, it is proved that the ratio of input voltage to output voltage is determined by the load to the transformer and the number of interdigital electrode pairs for the input and out