The Chaobai River basin, a biodiversity hotspot in Beijing, plays a crucial role in understanding the river"s ecosystem and improving protection quality through studies on large benthic animal biodiversity and community stability. In this study, 44 sampling sites were set up in the mountainous and plain sections of the Chaobai River basin, and surveys of large benthic animal communities and their diversity were conducted in September 2020 (autumn), December 2020 (winter), April 2021 (spring), and July 2021 (summer). Using data from these surveys, we analyzed the spatiotemporal changes in multidimensional biodiversity and community stability of benthic animals in the Chaobai River basin and explored the relationships between various biodiversity and community stability indices using Pearson correlation coefficients and generalized linear models. Results showed that seasonal changes in biodiversity and community stability of benthic animals in the Chaobai River were not significant, while differences between mountainous and plain areas were pronounced. The Margalef richness index and other species diversity indices were higher in the mountainous area, but the Pielou evenness index was lower. Functional diversity indices indicated richer functional traits and more redundant species in the mountainous section. Secondary productivity, turnover rate, and species competition intensity of benthic animals were lower in the mountainous area of the Chaobai River than in the plain area, while cohesion was higher, suggesting greater community stability in the mountainous area. Pearson correlation analysis revealed significant correlations between different biodiversity indices, while correlations between indices representing community stability were weak and not significant (p>0.05). Analysis of the correlation between diversity and stability found that more uniform species distribution, higher species richness, and greater niche differentiation led to higher secondary productivity, larger turnover rate, less species competition, and greater community cohesion, resulting in higher community stability. The most parsimonious models for community stability in both mountainous and plain areas favored taxonomic and functional diversity to explain changes in benthic animal community stability in the Chaobai River. Functional divergence (FDiv) was selected most frequently, indicating that differences in species trait abundance and interspecific niche complementarity are key factors affecting benthic animal community stability in the Chaobai River. However, only the model for secondary productivity in the plain area had relatively high explanatory power, while other models had low explanatory power, suggesting that long-term environmental factors may have a greater impact on benthic animal community stability in the Chaobai River.