Abstract: 【Objective】 To understand the community structure characteristic and diversity of the fish in Shahu Lake,Ningxia,providing support for fish diversity conservation and scientific management of Shahu Lake.【Methods】 Fishery resources surveys were conducted at five sampling sites in Shahu Lake [Holiday Hotel Pier（S1）,New Water Inlet（S2）,Lake Center（S3）,North Shahu Lake（S4）,and West Beach（S5）] in May,August,and November 2024. The fish species composition and ecological type classification were analyzed,dominant fish species and diversity,and the stability,structure similarity of that community were analyzed on the temporal and spatial distribution.【Results】 A total of 746 fish individuals were collected across the three surveys,belonging to 15 species,13 genera,5 families,and 3 orders. The Cyprinidae was the most numerous（9 species）,accounting for 60.00%. In the ecological type classification,carnivorous and omnivorous fish were the most numerous（7 species each）,both accounting for 46.67%;inhabiting the demersal layer fish were the most numerous（7 species）,accounting for 46.67%;and fish producing adhesive eggs were the most numerous（12 species）,accounting for 80.00%. The relative importance index（IRI） analysis showed that Sander lucioperca and Carassius auratus were the dominant species in Shahu Lake. On the temporal scale,the Shannon-Wiener diversity index of fishes ranged from 1.388 to 1.565,with an average of 1.448;the Margalef richness index ranged from 1.347 to 2.117,with an average of 1.803;and the Pielou evenness index ranged from 0.526 to 0.752,with an average of 0.637. The abundance/biomass comparison curve showed that on the temporal scale,the fish communities in May and November 2024 experienced intermediate disturbance,while the disturbance in August was minor;on the spatial scale,the fish communities at S1,S3,and S4 experienced intermediate disturbance,while the disturbance at S2 and S5 was minor. The community Jaccard similarity index across the three surveys ranged from 0.462 to 0.547,and the Jaccard similarity index among the five sampling sites ranged from 0.316 to 0.727.【Conclusion】 The fish community structure in Shahu Lake is relatively simple,and the diversity level is generally moderate. Its changes are primarily caused by the combined effects of anthropogenic disturbance（tourism development,water pollution）and fish invasion（Sander lucioperca）.

Key words: Shahu Lake, Ningxia, Fish, Community structure, Diversity, Temporal and spatial distribution