Ecological niche can be used as an indicator to symbolize the resources utilization capability of certain groups of related species and inter-species relationship, and it's essential for ecology research.A survey to determine the fishery in the Zhejiang Oufei reclamation area was conducted in May 2014. The index of relative importance (IRI) was measured to determine the dominant species of fish assemblage. The niche breadth and overlap of the dominant fish species were analyzed with the Bray-curtis similarity clustering and non-metric multidimensional scaling(MDS) analysis,and the differentiation of the niche was studied with canonical correspondence analysis(CCA),aiming to approach the community structure of fishery resources and related influencing factors in the area.The results showed that:(1)There are 12 dominant species,the main dominant species were Argyrosomus argentatus Houttuyn similar with that in 2007.(2)The niche breadth index varied from 0.31 to 2.32. Argyrosomus argentatus Houttuyn, Johnius belangerii,Pampus argenteus, Squilla orarotia,Portunus trituberculatus, Collichthys lucidus and Harpadon nehereus had large niche breadths.Niche overlaps varied from 0.01 to 0.95, Clupanodon punctatus and Lepidotrigla scaled searobins had a niche overlap value about 0.95. CCA results showed that the niche breadth and overlap of dominant species were closely related with the functional groups of species and habitat conditions, and they do not have a simple positive correlation. (3) Suspended matter had more important influence on the species spatial distribution than water temperature, salinity, pH and chlorophyll a, and the species spatial distribution was less affected by dissolved oxygen.These factors could account for 59% of the species variation.