Based on the flexural beam theory proposed by Timoshenko, this paper establishes a transfer matrix theory of the dual excitation stepped sandwich piezoelectric transducer in flexural vibration, The analytical theoretical model and FE simulation are used to calculate and analyze the first four order flexural vibration characteristics of the transducer, The results of the analytical theoretical calculation and the FE simulation are consistent in all flexural vibration modes of the transducer, The effective electromechanical coupling coefficient of the transducer is large in low order (first and second order) flexural vibration mode, and small in high order flexural vibration mode, The diameter ratio of the stepped front cover has a greater impact on the flexural resonance frequency and the amplification factor of the transducer, the larger the diameter ratio, the lower the flexural resonance frequency and the greater the amplification factor,