Abstract: Compared with conventional electromagnetic transformer, piezoelectric transformer has many advantages such as compact volume, high step-up ratio, non-flammability, and none-electromagnetic pollution. In this paper, the parameters of equivalent circuit of radial vibration mode piezoelectric transformer are measured through Y-parameter equivalent circuit model using Agilent-4294A impedance analyzer. The values of measurement and model are compared, and the causes of the differences are analyzed. Then the characteristics of variety of step-up ratio, output power, and efficiency with load are simulated and analyzed by turning the measured results into the formula.