Curved bridges account for over 45% of high-speed rail infrastructure, where the coupled effects of strong winds and curved superelevation can easily trigger train overturn accidents. The current standard TB 10621-2014 addresses only straight-line conditions and lacks frequency-domain evidence to support its claims. This study establishes a coupled model of a three-car train-10 m viaduct-150 mm superelevation. Employing the Realizable turbulence model and a UDF custom wind field, it systematically analyzes the aerodynamic response and spectral characteristics at 300 km/h for crosswinds, random pulsating winds, and China-hat gusts. The results indicate that: when wind blows from the curve"s inner side, lateral forces decrease by 14.5%–15.4% compared to straight sections, lift slightly increases, but the overturning coefficient surges by 33.07%–33.54% due to lever arm changes; When wind strikes from the curve"s outer side, lateral forces and lift increase by 12.6%–19.9% and 10.1%–16.6%, respectively. Frequency domain analysis indicates: Random pulsating wind energy exhibits broadband distribution (0.33–8.49 Hz), dominating low-frequency cumulative responses; China Hat gust energy concentrated between 0.33–1.49 Hz, with the overturning moment"s dominant frequency at 0.83 Hz approaching the natural frequency of the vehicle-bridge system, readily inducing short-term resonance. At 25 m/s wind speed, China Hat gusts caused the highest overturning coefficient increase of 33.54%, exhibiting the most pronounced transient impact effect. This study fills a gap in research on curve-wind-ultra-high coupling spectra, providing frequency-domain quantitative basis for dynamic speed limit design in high-wind zones.