Abstract: Investigating the impact of hydrological connectivity on waterbird diversity is crucial for optimizing waterbird habitat structure and maintaining wetland ecological functions. Using Xianghai National Nature Reserve in Jilin Province as the study area, this study systematically analyzed the response characteristics of waterbird diversity to changes in wetland hydrological connectivity from 2014 to 2023, employing field surveys and a connectivity assessment model. By evaluating waterbird community characteristics and diversity during periods of differing hydrological connectivity, the influence of wetland hydrological conditions on waterbird diversity was explored. The results indicate that: Between 2014 and 2023, waterbirds of the orders Charadriiformes and Anseriformes constituted approximately 52.59% of the waterbird community within Xianghai Reserve. The overall trend in waterbird diversity indices showed an initial increase followed by a decline. Significant temporal variations were observed in the Simpson diversity index, Shannon-Wiener diversity index, Margalef species richness, and Pielou evenness. A significant coupling relationship exists between waterbird diversity and wetland hydrological connectivity. Waterbird diversity was higher during periods of high hydrological connectivity. As connectivity decreased, waterbird populations became unevenly distributed, community diversity declined, and community structure tended towards simplification. Enhancing the management of wetland hydrological connectivity is therefore essential for improving waterbird diversity and sustaining wetland ecological functions.