This study proposes a passive bionic noise reduction strategy using serrated trailing edge (TE) designs to be applied to the aero-train's ground-effect wing. The aim is to mitigate TE noise by suppressing the tail vortex under high-speed and near-wall conditions. Three different serrated TE designs were numerically investigated via large eddy simulation, combined with Möhring acoustic analogy theory under Ma = 0.3 to reveal their noise reduction effects. The noise reduction mechanism was analyzed from the perspective of the flow characteristics in the TE boundary layer. The results indicate that all serrated TE designs achieve noise reduction, with the TE2 exhibiting superior performance. This outcome is linked to the ability of serrated TE designs to moderate boundary layer airflow separation and backpressure gradients, facilitating smoother transitions and lessening wake vortex intensity, thereby reducing turbulence-induced noise. Designs featuring wider serration gaps and sharper edges further enhance noise attenuation.