Abstract: To establish a high-precision and regionally adaptive depth datum for the Bohai and Yellow Seas, this study integrates satellite altimetry data with multiple global tidal models to develop a hybrid modeling and accuracy evaluation framework. Based on long-term observations from 23 tide gauge stations, the applicability of four global tidal models—DTU16, EOT20, FES2014, and FES2022—was systematically assessed. Results indicate that the FES2014 model exhibited the best performance among short-period tidal models, with the lowest RSS value of 4.57 cm for the eight major tidal constituents. To address the limited accuracy of existing tidal models in representing long-period constituents such as the annual (Sa) and semi-annual (Ssa) tides, along-track harmonic constants of Sa and Ssa were extracted from TOPEX/Poseidon and Jason satellite altimetry data (1993-2021) without inverse barometric correction. Validation against tide gauge records shows that the root mean square errors of Sa and Ssa amplitudes are 3.02 cm and 2.89 cm, respectively, demonstrating the reliability of this method for long-period tidal modeling. By combining 11 short-period constituents from FES2014 with long-period constituents derived from satellite altimetry, a comprehensive hybrid tidal model was constructed to generate a depth datum surface covering the Bohai and Yellow Sea region. The resulting datum values range from 51.49 cm to 530.04 cm, exhibiting significant spatial variation. Compared with the model based solely on FES2014, the hybrid model shows a notable improvement in accuracy, reducing the root mean square error from 19.44 cm to 11.66 cm at tide gauge locations—a 40% improvement. This enhancement is primarily attributed to the improved treatment of long-period constituents and the strong consistency between uncorrected satellite altimetry and in situ observations. Comparison with existing depth datum values at tide gauge stations reveals persistent regional deviations, reflecting spatiotemporal inconsistencies arising from differences in constituent selection and computational methods used in historical practices. These findings highlight the need to implement localized data assimilation strategies in key areas to enhance compatibility with existing datums. The proposed hybrid tidal modeling approach offers a systematic solution for high-precision depth datum construction in the Bohai and Yellow Seas. It confirms the effectiveness of multi-source data integration in improving model accuracy and regional adaptability and provides a theoretical and technical basis for hydrographic surveying, vertical datum unification, and marine engineering applications.