Abstract: To investigate the necessity of high-resolution air-sea-wave coupling for improving short-term numerical weather prediction, a coupled sea-air-wave model consisting of ROMS (Regional Ocean Modeling System), WRF (Weather Research and Forecast model) and WW3 (WAVEWATCH Ⅲ) is established, and a set of sensitivity experiments is conducted. The Meiyu rainfall events are selected in June 2023. We analyze the spatiotemporal impact characteristics of coupling effects on precipitation and related meteorological fields. The results demonstrate significant spatiotemporal heterogeneity in atmospheric responses including precipitation, 2m air temperature, 10 m wind field, and specific humidity. The coupling-induced differential signals exhibited landward propagation characteristics from the ocean, with localized heavy precipitation differences reaching 10 mm/3h within 36 hours and extensive daily precipitation differences exceeding 50 mm/day over regional scales within 3 days in the land surface. Near-surface temperature and wind field differences attained 10% of background values by 36 hours. Vertically, the coupling impacts on wind and moisture fields progressively but quickly propagated upward with forecast time. The wind field response propagated faster than moisture variations, with differences penetrating the entire troposphere (up to 100 hPa) and covering the study domain within 36 hours. Vertical velocity deviations triggered low-level dynamic adjustments that accelerated moisture vertical transport. Furthermore, the coupling effects induced discernible adjustments in 7-day atmospheric circulation patterns, with substantial geopotential height differences over land-based vortex systems at 500 hPa. This study confirms that air-sea-wave coupling exerts significant impacts on atmospheric element predictions along China"s southeastern coast within 36 hours, while generating non-negligible modifications to circulation patterns. The implementation of air-sea-wave coupling proves essential for enhancing short-term weather forecasting in Southeast China.