Abstract: As a core component of marine exploration systems, the structural parameters of an electromagnetic pulse sound source decisively influence its performance. This study investigates the effects of key parameters—namely, trace width and radiating plate thickness—on the sound pressure level (SPL) and dominant frequency of the sound source. Forty-five sets of comparative experiments (5 energy levels × 3 trace widths × 3 radiating plate thicknesses) were designed and conducted in an anechoic water tank. The center of the hydrophone was aligned with the center of the sound source’s radiating surface, facing each other directly on the same horizontal plane at a separation distance of 0.3 m. Each experimental condition was repeated five times. From the 225 raw measurements obtained, the mean values and standard deviations of the dominant frequency and SPL were calculated. The results show that: (1) within the trace width range of 0.15–0.40 mm, the dominant frequency first increases and then decreases with increasing trace width, whereas the SPL first decreases and then increases; (2) within the radiating plate thickness range of 2–4 mm, the dominant frequency first decreases and then increases with increasing thickness, while the SPL first increases and then decreases. These findings provide a preliminary experimental basis and practical design guidance for optimizing the key structural parameters of electromagnetic pulse sound sources.