Three laminated disc bending vibration transducer was studied in theory under the fixed boundary condition by Rayleigh method. The resonant frequency and the effective electromechanical coupling coefficient were derived. The variation of transducer resonance frequency and the effective electromechanical coupling coefficient of the transducer with size parameters was analyzed through numerical calculation, and comparison was made between the theoretical value and the finite element simulation results. The results showed that the transducer structure parameters had great influence on the resonant frequency and the effective electromechanical coupling coefficient. The effective electromechanical coupling coefficient would have a maximum value changing with the thickness of sheet metal and ceramic plate, and the radius ceramic plate when other dimensions was determined. This would provide theoretical support for the design and further application of three laminated flexural vibration transducer.