Objective: The study aims to explore the association between intake of dietary flavonoids and global cognition, domain-specific cognition and mild cognitive impairment (MCI) in middle-aged and older adults in China. Design: A cross-sectional study. Methods: This study used baseline data collected during 2021-2023 from the Chinese Square Dance Cohort. Dietary information was collected using a semi-quantitative food frequency questionnaire, and flavonoid intakes were calculated. Cognitive function was evaluated using a battery of neuropsychological tests, and global cognition was assessed using the composite z-score. Participants with MCI were diagnosed by Petersen's criteria. The relationship between flavonoid intake and cognitive score was determined using multiple linear regression and presented as β values with 95%CIs. The association of flavonoid intake with MCI was evaluated using logistic regression models and presented as odds ratios (ORs) with 95%CIs. Results: Among 3990 middle-aged and older participants, the median (P25-P75) age was 63 (59-67) years, and 85.05% were females. After adjusting for various covariates, compared to the lowest quartile (Q1), the highest intakes (Q4) of total flavonoids, anthocyanidins and flavan-3-ols, flavanones, flavones, flavonols, procyanidins, and isoflavones were associated with higher composite z-scores, with β values (95%CIs) of 0.12 (0.06, 0.17), 0.15 (0.10, 0.21), 0.09 (0.04, 0.15), 0.11 (0.06, 0.17), 0.08 (0.02, 0.13), 0.09 (0.03, 0.14), and 0.09 (0.04, 0.15), respectively. In addition, higher dietary intakes of anthocyanidins and isoflavones were associated with lower odds of MCI, where the corresponding ORs (95%CIs) for Q4 were 0.69 (0.51, 0.94) and 0.72 (0.54, 0.97), respectively. Conclusion: Higher flavonoid intakes were related to better cognitive function. These findings suggest a beneficial effect of flavonoid intake on the cognitive aging process.