A typical bimodal spectrum in West Africa was obtained based on the measured wave data, and the transformation, deformation, and spectral evolution characteristics of irregular waves on typical beaches under the conditions of different energy proportions of wind waves and swells were studied through physical model experiments. The results demonstrate significant differences between bimodal spectral waves and unimodal spectral waves in terms of significant wave height variation, spectral peak energy evolution, and nonlinear interaction. The increase in the significant wave height for bimodal spectral waves is primarily governed by the shoaling process of low-frequency swell components, with higher swell proportion leading to larger maximum wave height before wave breaking. Compared to unimodal spectral swell, the swell spectral peak of bimodal spectral waves exhibits faster energy growth during transformation and slower energy dissipation after wave breaking. Nonlinear interaction between swell and wind wave spectral peaks induces energy transfer from high-frequency wind wave components to low-frequency swell components, resulting in relative energy growth of the swell spectral peak in bimodal wave spectrum.