Abstract: Understanding the spatial patterns of fish multi-dimensional biodiversity is essential for guiding conservation strategies in aquatic ecosystems. We selected the Longyangxia Reservoir, one of the largest reservoirs in the upper reaches of the Yellow River, as our study area. We analyzed the patterns of β diversity, along with its turnover and nestedness components and driving factors, across taxonomic, functional, and phylogenetic dimensions using three different data types: species occurrence, abundance, and biomass. Our results revealed that: (1) for the overall fish community, turnover components dominated taxonomic, functional, and phylogenetic β diversity based on species occurrence data, whereas nestedness components dominated when using abundance and biomass data; (2) for native fish species, turnover components primarily drove taxonomic β diversity based on species occurrence data, while nestedness components dominated functional and phylogenetic β diversity, with nestedness components prevailed across all dimensions when using other data types; (3) multiple regression on distance matrices (MRM) analysis indicated that distance from the dam and proportion of non-native species significantly influenced all multi-dimensional β diversity patterns. Our findings underscore the importance of integra ting multiple data types and diversity dimensions to capture complementary insights into biodiversity dynamics, enhancing our ability to detect and interpret patterns and processes in community composition. Furthermore, the β diversity in Longyangxia Reservoir is largely shaped by nestedness components, with a certain proportion of turnover components. This suggests that conservation efforts should prioritize the most biodiverse sites and consider multiple habitats throughout the reservoir to effectively preserve fish biodiversity.