Abstract: In order to grasp the current status of fish resources in the sea area,according to the fish data obtained from the bottom trawling survey of fishery resources in the adjacent waters of Shengsi Archipelago in April 2017,the relative importance index,Shannon-Weaver index,biomass curve and other methods were used.We analyzed the fish species composition,dominant species,spatial distribution of species quantity,and biodiversity in this sea area to perfect the research content of fishery resources in Zhoushan sea area,and provided scientific basis for rational utilization and protection of fishery resources in Zhoushan coastal waters.A total of 33 fish species had been identified in this area,among which the dominant species were Colichthys lucidus, Pampus argenteus, Harpodon nehereus and Coilia mystus.Compared with historical data,the number of fish species in this sea area has decreased sharply,and the dominant species have changed significantly.The sum of the tails accounted for 86.48% of the total catches,and the sum of the dominant species quality accounted for 77.67% of the total catches.Since C.lucidus, P.argenteus, H.nehereus and C.mystus were economic fish,the economic fish in the surveyed sea area accounts for a relatively large proportion and has high economic value.The number of fish species in each station was between 9 and 20,and the number of fish species in the northern area of the surveyed sea was relatively high,possibly because the northern area of the surveyed sea was open sea,relatively far from the island,and relatively less suffered from human interference.The biodiversity analysis showed that the higher position(H') 10 indicated that the population structure of the western sea area of Shengsi Archipelago had higher complexity and the evenness index(H') value was lower,which might be due to the low diversity index caused by the pollution of Zhoushan waters.The results of cluster analysis showed that at the 60% similarity level,each survey station could be divided into 4 groups,and the characteristic species that had a great influence on the similarity were mainly Miichthys miiuy,P.argenteus,H.nehereus and C.mystus.The spatial difference of fish community structure in this sea area was quite large,which might be due to the large difference in the dominance of dominant species in different stations,resulting in a large difference in the basic characteristics of the community;the overall distribution of the fourth group of stations showed the southwest-northeast trend,located near the island of Shengsi and Lühua xiang,which might be related to the hydrological environmental factors of the coastal waters,which made the stations in this group had a higher degree of similarity;most of the stations with higher numbers of fish were located near Lühua xiang.It might be because spring was the main spawning season for fish,and the sea area was a spawning ground for fish.The bait was relatively abundant near the islands and reefs,which attracted most fish to inhabit here.According to ABC curve analysis,the spring curve was stable,and the biomass dominance curve had always been below the abundance dominance curve,indicating that the fish community in the adjacent waters of Zhoushan Shengsi Archipelago had been seriously disturbed.It might be that the waters were greatly affected by human factors.Its stability was reduced.