We analyzed data from the investigation of fishery resources in Dafeng, off the north coastal waters of Jiangsu Province, east of China, to examine the community structure and influences upon it. Cluster analysis was used to divide the community structure based on the spatial distribution of species composition, diversity and dominant species. We found that during the spring (May) and autumn (November) the coastal water fishes in the northern Jiangsu shoal could be classified into three communities:the coastal waters to the west of the sand ridge; the sea of the central sand ridge; and the tidal creek. The difference in fish community structure was also demonstrated by the total number of fish species in spring[tidal creek (15)>sand ridge (11)>coastal (3)]; and autumn[(tidal creek (18)>coastal (12)>sand ridge (11)]. There was a similar diversity index in spring[tidal creek (1.57,1.89), sand ridge (1.19,1.57)>coastal (0.51,0.69)]; and autumn[tidal creek (1.54,1.54)>coastal (1.02,0.96)> sand ridge (0.92,0.83)]. The tidal creek and open sea are adjacent, so the sand ridge obstructs the sea fish in moving offshore when encountering the end of the tidal creek and makes the benthic fishes stay at the bottom of the ditch which render the accumulation of species, diversity increasing. The spatial distribution of dominant species shows that tidal creek species are mostly and other spawning fishes; the sand ridge mostly consists of and other filter-feeding fishes. We conclude that the community structure of fishes in the sandy ridge and tidal creek in the northern Jiangsu shoal varies, and that topographic changes and environmental change caused by the terrain are the main reasons for this. Using the topography of the tidal creek and sand ridge is an advance that not only focuses on the environmental factors influencing fish community structure changes, but also provides a reliable basis for the management and conservation of fisheries in Subei shoal.