Abstract: In traditional set pair analysis, the identity and opposition coefficients are typically assigned fixed values, which fails to adequately capture the complexities involved in practical water resources carrying capacity (WRCC) evaluation.To address this limitation, this study comprehensively analyzed the deviations of indicators within the WRCC system from their ideal values, determined opposition relationships of the relative connection number, and established a regional water resources carrying capacity evaluation method based on the relative connection number.This approach was applied to evaluate and diagnose obstacle factors for four prefecture-level cities in the Jianghuai hilly region of Anhui Province, while carrying comparative analysis against the TOPSIS method.The results indicated: ① From 2011 to 2022, the regional WRCC showed a fluctuating upward trend, with the mean set pair potential increasing from 0.49 to 0.65;② The primary obstacle factors included water yield modulus, per capita water supply, per capita water resources, ecological water use rate, and per capita GDP; ③ Compared with the TOPSIS method, the relative connection number-based WRCC evaluation approach produced generally consistent results while it more effectively capture data uncertainty through refining opposition relationships.It also demonstrated higher precision in reflecting indicator trends and greater sensitivity.These findings can provide a reference for regional water resources management.