Objectives Growing evidence suggests that elevated CDAI may confer protection against various health conditions, despite the extensive examination of the association between the composite dietary antioxidant index (CDAI), an essential metric of antioxidant intake, and the risk of chronic diseases. However, the correlation between CDAI and the likelihood of age-related cataracts is inadequately characterized. To address this gap, we performed a cross-sectional investigation to evaluate a potential link between CDAI and cataract occurrence. Method The National Health and Nutrition Examination Survey (NHANES), which ran from 2005 to 2008, provided the data for this investigation. We evaluated dietary antioxidants using two 24-hour food recall interviews. To derive CDAI, we concentrated on six specific antioxidants. Based on a history of cataract surgery, we indirectly evaluated age-related cataracts. Logistic regression models were utilized to analyze the correlation between CDAI and cataract risk. Additionally, we investigated nonlinear relationships using curve-fitting methods and performed subgroup analyses to evaluate potential effect modifications. Results This research included 8,582 participants, of whom 5,296 were free of cataracts and 2,881 were diagnosed with cataracts. Compared with normal subjects, the CDAI of cataract patients was lower (-0.32 ± 3.47) (p < 0.001). In multivariate logistic regression, CDAI as a continued variable was inversely correlated with cataract risk [0.95 (00.93–0.97), p < 0.0001]. We looked at CDAI as a categorical variable and discovered that people in Q3 had a much lower risk of cataracts than people in Q1. For each unit increase in CDAI, cataract risk decreased by 15% [0.85(0.72–0.99), p = 0.039]. Subgroup analyses and interaction tests showed that factors like age, sex, level of education, marital status, tobacco use, alcohol consumption, hypertension, hyperlipidemia, and diabetic mellitus did not significantly change the negative relationship between CDAI and cataracts. Conclusions The inverse relationship between the CDAI and cataract risk persisted even after controlling for other possible factors. This suggests that eating a diet rich in antioxidants may reduce the risk of cataract.