[Objective] This study centers on the dike fields of the spur dike group in the Yangtze River Estuary, a typical tidal estuary where complex water-sediment dynamics and diverse dike layouts jointly shape deposition processes. Its core objectives are twofold: first, to unravel the coupling mechanism through which dynamic factors (e.g., runoff, tides) and geomorphic parameters (e.g., dike spacing, initial water depth) jointly regulate sediment deposition intensity in tidal estuarine dike fields; second, to develop a reliable empirical formula for predicting such deposition intensity. By addressing the gap in existing research—where the integrated effects of dynamic and geomorphic factors are often overlooked—this study aims to provide robust theoretical support for optimizing the design of spur dike groups and enhancing the accuracy of deposition forecasting in the Yangtze River Estuary and analogous tidal estuarine systems worldwide. [Methods] The dike fields of the spur dike group in the north passage of the Yangtze River Estuary, a key area of the Yangtze River Estuary Deepwater Channel Regulation Project, were selected as the research focus. Long-term, systematic measured data were analyzed, including dike field topographic surveys, hydrological observations, and sediment monitoring records. Correlation analysis was first performed to examine how deposition intensity relates to key dynamic factors (upstream runoff from the Datong Hydrological Station, suspended sediment concentration, offshore tidal range, suspended sediment particle size) and critical geomorphic parameters (relative spacing of spur dikes, initial water depth of dike fields, spur dike length, dike field depth). Using dimensional analysis and the Buckingham π theorem, a comprehensive dynamic parameter was constructed by integrating the four dynamic factors, synthesizing their combined influence on water-sediment transport and deposition. Simultaneously, a set of geomorphic parameters was established, incorporating spur dike spacing, length, and dike field depth to quantify the impact of spur dike group layout and dike field topographic features on local flow patterns and sediment trapping. A power function model was then used to quantify the coupling relationship between the comprehensive dynamic parameter and geomorphic parameters, and an empirical formula for deposition intensity was derived. Finally, the formula was validated using measured data from representative dike fields, including those unaffected by subsequent engineering and those influenced by phased projects. [Results] 1) As the Yangtze River Estuary Deepwater Channel Regulation Project advanced through three phases, total sediment deposition in dike fields increased significantly (from 15.48×10⁶ m³ in Phase I to 128.01×10⁶ m³ in Phase II), confirming the spur dike group’s strong sediment-trapping effect. 2) Deposition intensity was positively correlated with runoff (higher runoff carries more sediment to dike fields) and sediment concentration (more available sediment for deposition), but negatively correlated with tidal range (larger tidal range strengthens ebb currents, enhancing offshore sediment transport) and sediment particle size (coarser particles settle before reaching dike fields or are easily resuspended by strong flows). 3) Among geomorphic parameters, initial dike field water depth showed a strong positive linear correlation with deposition intensity (deeper water provides more deposition space and reduces flow velocity, favoring sediment settlement), while spur dike relative spacing had weak correlation (R²=0.44), due to interactions with factors like flow blockage (too small spacing) or uneven energy distribution (too large spacing). 4) The comprehensive dynamic parameter correlated highly (R²=0.94) with annual deposition in undisturbed dike fields (TS1, TS2), effectively capturing dynamic drivers of deposition; geomorphic parameters correlated strongly (R²=0.96) with initial deposition, clearly distinguishing differences between dike fields in the same spur dike group. 5) The empirical formula showed excellent agreement with measured data: it matched well with the measured deposition intensity of TS1, TS2, and TS8 (used for fitting analysis) and effectively reflected the deposition intensity of TN7, TN8, and TN9 (used for validation in the second-phase project). Even for dike fields affected by phased engineering or new structures (e.g., a 21 km sediment barrier), the formula still successfully captured the overall deposition trend. [Conclusion] This study makes three key contributions: it innovatively integrates dynamic factors and geomorphic parameters into a unified analytical framework for Yangtze River Estuary spur dike group dike fields, overcoming the limitations of previous single-factor research; the constructed comprehensive dynamic parameter and geomorphic parameters effectively quantify the combined effects of water-sediment dynamics and dike layout/topography on deposition, making complex processes interpretable; the empirical formula, with high applicability and accuracy, offers a reliable tool for tidal estuarine dike field deposition prediction.