Sediment transport is a fundamental issue in the study of coastal and estuarine environments, holding significant scientific importance and practical value for the evolution of estuarine geomorphology, ecological environment, and engineering construction. This paper takes the estuary of the Moyang River as an example, based on the sea current, wave and suspended sediment concentration data measured by ship and bottom tripod, analyzes the alongshore and cross-shore transport trends of suspended sediment on the fixed cross-section of the Moyang River estuary, and calculates the sediment transport flux. It explores the sediment transport mechanisms and patterns in wave-tidal estuaries, with the main findings including: (1) During the flood season at the river mouth, the sediment transport is mainly controlled by the runoff, with the sediment transport flux increasing as the flow flux increases. The alongshore and cross-shore sediment transport reaches the maximum value during the neap tide with the largest flow, which are 111.9 g/(m²·s) and 269.5 g/(m²·s) respectively. At the mouth bar in the flood season, the sediment transport is jointly controlled by waves and tides. The alongshore sediment transport is consistently westward along the coast during both spring and neap tides, while the cross-shore sediment transport is dominated by the ebb tide during the spring tide with an offshore transport of 4.0 g/(m²·s), and by waves during the neap tide with an onshore transport of 19.0 g/(m²·s). (2) During the dry season, the mouth bar is primarily influenced by tidal currents and wave action. Sediment transport along the vertical shore predominantly occurs due to falling tidal currents moving seaward, while coastal transport is governed by wave energy, resulting in an eastward movement under the influence of wave-generated coastal currents. On the eastern side of the mouth bar during this season, tidal currents and waves also play a significant role; vertical shore transport is mainly driven by rising tides during spring tide periods before transitioning to offshore transport as tidal forces diminish. Coastal transport remains affected by wave-induced coastal currents and continues its eastward trajectory. (3) During the flood season observation period, the offshore transport at the river mouth is significant, and the flow direction of each water layer is consistent vertically. During the neap tide, there is a differentiation in the flow direction of the water layers, with the surface layer transporting offshore and the bottom layer onshore. At the mouth bar, the flow direction of each water layer is relatively consistent vertically during both spring and neap tides. Still, after tidal averaging, the spring tide shows offshore transport in all water layers, while the neap tide shows onshore transport in all water layers. During the neap tide, the influence of waves is evident, with the onshore transport ratio reaching 79%. (4) Under the influence of runoff and ebb current, the mouth of Moyang River estuary mainly carries sediment to the sea. The most significant factors affecting sediment transport at the mouth bar are the seaward tidal currents and the alongshore sediment movements driven by waves.