Abstract: Biodiversity is not only the key factor to maintain the stability of the ecosystem, but also the basis of human survival and sustainable development. Both dominant and key species play important roles in maintaining biodiversity and ecosystem stability. Therefore, the selection of key species is the basis of biodiversity conservation and one of the beneficial methods to analyze and explore the structure of the ecosystem. As a typical nearshore island in the north of China, Miaodao Archipelago has important value in ecosystem services and biodiversity maintenance. Phica largha pallas and Neophocaena Asiaeorientalis sunameri are representative flagship species. In the past, researchers have carried out a systematic and comprehensive investigation of the ecological environment, vegetation status, and plankton distribution in the adjacent waters of the region, but there are few reports on the scientific research on the fishery resources in the adjacent waters. In recent decades, the structure of fishery resources in the Bohai Sea and the North Yellow Sea, which are important fishery waters in northern China, has changed to some extent due to the influence of human activities and climate change. The adjacent sea area of Miaodao Archipelago plays an important role in maintaining fishery resource structure and biodiversity in the Bohai Sea and the North Yellow Sea as an important migration channel and habitat. Therefore, it is urgent to carry out systematic research on fishery communities in this area to make up for the lack of relevant data. This study focuses on the key species of the bottom fishery community in this area. Since there are many small benthic invertebrates and small fishes in the bottom fishery community in the adjacent waters of Miaodao Islands, it is impossible to obtain feeding data by traditional gastric content method and published literature. Therefore, important and dominant species with IRI>100 were selected as the research objects for this key species screening. Remove the interference of a smaller number of redundant species. Based on the feeding relationship between important species and dominant species (IRI>100) in bottom fishery organisms in the adjacent waters of Miaodao Islands, this study calculated the topological index of the structure based on the topological structure of food web and network analysis method, and screened key species. The results showed that the study area contains a total of 37 important and dominant species (IRI>100), 223 feeding relationships, node density of 0.17, connection density of 6.03, connection complexity index of 12.21, and interspecific association degree. The index is 0.16, the feature path length is 2.10, and the average clustering coefficient is 0.30. Comprehensive topological index ranking (D, D_out, D_in, BC, CC, IC, TI¹, TI³, TI⁵, K, K_b, K_t, F and ^DF), screening for export mantis shrimp (Oratosquilla oratoria), Japanese drum shrimp (Alpheus japonicus), Pennahia argentata, Chaemrichthys stigmatias, Glossaulax didyma are the main key species in the study area. Among them, mantis shrimp and white jellyfish are the key predators, gobies are the key intermediate species, and the platy snail is the key bait species, while the Japanese drum shrimp is between the key intermediate species and the key bait species. Most species in the regional food web are likely to be very close “neighbors”, and negative impacts can spread rapidly and widely throughout the food web. For example, the effects of disturbances such as overfishing may be more widespread in this marine ecosystem. However, rich interaction networks quantified by high connectivity and low path lengths may also suggest that strong effects can spread rapidly throughout the marine food web, reducing the overall impact of any particular fluctuation. The results can provide basic data and a scientific basis for further understanding of the marine food web structure in the adjacent waters of the Miaodao Islands and the protection of biodiversity. In the future, more methods should be combined to carry out a more systematic study on the seasonal and interannual changes of key species in this area, to provide information for the adjacent islands in my country. The related research on the structure of the marine food web provides a more scientific and valuable reference.