This paper presents the development and validation of a two-dimensional (2D) axisymmetric finite element model (FEM) for a high-power ultrasonic transducer. The model was constructed through a sequential simulation workflow comprising static, modal, and harmonic analyses to capture preloading stress distribution, resonant frequency, nodal plane position, and vibration amplitudes. Experimental measurements showed excellent agreement with the simulations, with discrepancies below 2% for both resonant frequency and working-point amplitude, confirming the model’s reliability. The validated FEM framework was then applied to a reverse engineering problem, aiming to identify suitable material combinations for transducer components when detailed manufacturer specifications were unavailable. By iteratively adjusting material parameters and comparing predicted outputs with target operational characteristics, the model demonstrated its capability to reconstruct plausible material configurations and predict their influence on resonance behavior. Results highlight that even auxiliary elements such as bolts and electrodes significantly affect the nodal plane and vibration response, providing valuable guidance for fixture design and cooling integration. This study demonstrates the practical utility of a validated 2D FEM model in both design optimization and reverse engineering of ultrasonic transducers.