Abstract: Metacommunity theory aims to explore the formation mechanisms of species composition and biodiversity from the spatial perspective, while temporal dynamics also contribute to metacommunity structure. In this study, we investigated the characteristics, temporal variations and drivers of fish metacommunity structure, as well as the key locations and species that contributed more to β diversity by conducting the field surveys in July 2010 and March 2019 in the nine locations of the Poyang Lake. Our analysis indicated that there were the apparent variations between 2010 and 2019. 55 and 52 species were separately collected in 2010 and 2019. The species compositions differed significantly (P<0.05). The structure of the fish metacommunity changed from Clementsian to Gleasonian gradient, which implied that although the species compositions of the local communities always changed along the environmental gradient, the similarities between the local communities increased from 2010 to 2019, and there was a trend of homogenization. β-diversity (βtotal) decreased from 0.36 to 0.34 and βrepl increased from 57.5% to 63.2%. β-diversity among the locations decreased from 0.50-0.91 to 0.33-0.81. βtotal, βrepl and βrich were not significantly affected by environmental factors such as the distance from the main stream of the Yangtze River and whether there are tributaries converging or not and spatial factors in 2010 (P>0.05), but significantly affected by environmental and spatial factors in 2019 (P<0.05). The locations with high Local Contribution to Beta Diversity (LCBD) shifted from the lateral channel between Yangtze River and Poyang Lake. The species with high Species Contribution to Beta Diversity (SCBD) were Silurus asotus,Ctenopharyngodon idella,Coilia nasus,Cobitis sinensis and Hemiculter bleekeri in 2010, while the species with high SCBD were Xenocypris argentea,Sinodella sinensis,Parabramis pekinensis,Cobitis sinensis and Misgurnus anguillicaudatus in 2019. The results indicated that the interaction between fish communities and fish dispersal caused the changes of fish community structure and key sites in Poyang Lake area in recent ten years. At the same time, according to the existing research results, overfishing and habitat degradation may also affect the fish community structure in Poyang Lake. In order to protect the fish diversity in the Poyang Lake and the middle-lower Yangtze River floodplain, it was suggested to reduce human activities, such as reclamation, sand mining, and pollution discharge, to carry out habitat degradation assessment and restoration, and to restore connectivity between rivers and lakes.