<p>In recent years, the rapid economic development and overexploitation of resources have exerted a certain degree of impact on the ecosystem of the Yalu River estuary. To achieve a more comprehensive understanding of the trophic structure within this marine ecosystem and to better protect and utilize the biological resources in the nearshore waters of the Yalu River estuary, this study employs stable isotope analysis, supplemented by isotopic niche modeling and Bayesian metrics. These methods are used to elucidate the trophic structure of various macrofaunal groups in the Yalu River estuary. The results of the stable isotope analysis reveal that terrestrial inputs have influenced certain benthic crustaceans, leading to elevated <i>δ</i>¹⁵N values. Our findings indicate that among the 19 macrofaunal species identified in the Yalu River estuary, three distinct trophic groups exist, with minimal overlap in isotopic niches between species within each group. Furthermore, the specialization index demonstrates that organisms in two of these groups rely on a limited number of food sources, suggesting that the Yalu River estuary is currently experiencing a phase of high productivity. This research contributes to a deeper comprehension of the food web and trophic structure of estuarine ecosystems, providing a theoretical foundation for the sustainable management and utilization of biological resources in the Yalu River estuary.</p>