Abstract: The Yellow River Delta (YRD) is the largest and fastest-growing newly formed estuarine tidal wetland in China’s warm and humid zone. Innovative ecological restoration and water-sediment allocation technologies have become key tasks for safeguarding and promoting high-quality development in the Yellow River Basin in the new era. Under the evolving environmental conditions of the basin, significantly shaped by industrial and agricultural activities, crucial challenges relating to sediment distribution and ecological restoration require further investigation. Prominent among these are the uncoordinated water-sediment regime, coastal erosion, Spartina alterniflora invasion, and ecological fragility evident in the tidal-flat wetlands of the YRD. Preliminary progress has been made using field surveys, remote sensing interpretation, physical and mathematical modelling, and engineering experiments, addressing landscape and habitat evolution, hydrological connectivity, spatio-temporal distribution of water and sediment, and ecological restoration technologies. Firstly, the dynamic landscape/habitat evolution and hydrological connectivity of the YRD tidal-flat wetlands over the past 40 years were clarified. The wetland types have changed considerably, shifting from natural wetlands to artificial ones (especially aquaculture ponds and salt pans), with evident spatial differences in landscape evolution. Wetlands in the Qingshuigou area have expanded, while natural wetlands in the Yiqian’er area have declined. Transformations have occurred both within natural wetlands and from natural wetlands to non-wetlands. Following the implementation of water and sediment regulation, sediment accumulation in the river-mouth channel of the Yellow River has been eased, and tidal channels have developed rapidly; however, they display a network characterised by stronger linear than circular connections in the early development stage, and their structural connectivity remains low. The impact of ecological water supplementation on structural connectivity mainly depends on the construction of water systems in wetland restoration areas, with the number of artificial ditches being significantly positively correlated with the comprehensive connectivity index. Secondly, a spatio-temporal interaction model for water and sediment allocation in the YRD was proposed, aiming to optimise flood resource utilisation and effectively coordinate the functions of plain reservoirs, the Qingshuigou flow path, and the Diaokouhe flow path. This interactive spatial-temporal configuration of water and sediment is selected to develop the principal channels for ecological water replenishment in the Yellow River Delta along the ten rivers flowing into the sea. Utilising water and sediment regulation and reservoir flood discharge (e.g., Xiaolangdi), ecological water replenishment is conducted in different reaches (upper, middle, and lower) of the main flow route according to seasonal combinations of incoming water and sediment, ecological water demand periods, and channel erosion-siltation dynamics, while maintaining a basic balance of sediment transport and deposition. Finally, a cascade management approach—based on the Spartina alterniflora diffusion risk zones—and Suaeda restoration measures—through micro-topographic transformation—have been initially applied in the demonstration areas of the northern shore and Qingshuigou in the YRD. The expansion risk levels of Spartina alterniflora within the national nature reserve of the YRD were classified; control techniques for the Level-I zone (where the original ecosystem has largely been replaced) include cutting + double ploughing, cutting + flooding, cutting + double ploughing + biological replacement with Suaeda salsa, and cutting + double ploughing + biological replacement with reed. The micro-topography restoration mainly adopted the techniques of Fulong Shugou (Mound-Ditch Modeling) and pit-shape restoration. The seeds of Suaeda are retained at the pit bottoms, while nutrient-enriched fine soil from ridges flows into the depressions; plant growth and leaf decomposition further enhance nutrient accumulation. These results provide scientific and technological support for estuarine planning in the YRD, optimisation of hydrological connectivity schemes, and implementation of ecological protection measures.