Background: Exercise capacity serves as a direct representation of cardiac function. The Duke Activity Status Index (DASI), a self-administered 12-item questionnaire, covers aspects of daily living, household tasks, sexual function, and physical activity. Although widely used to evaluate exercise capacity, its validation in Chinese cardiovascular disease (CVD) patients has not been thoroughly explored. Considering the significant cultural and lifestyle differences between China and Western countries, which may influence Chinese patients’ comprehension and responses to DASI, our objective is to culturally adapt DASI for Chinese patients with CVD to ensure its precision in assessing exercise capacity. Methods: The cultural adaptation of the original DASI questionnaire into Chinese followed a rigorous process to ensure its validity, reliability, and sensitivity to Chinese CVD patients. The study included 107 outpatients diagnosed with CVD who completed the DASI and cardiopulmonary exercise testing (CPET). Cronbach’s alpha, Spearman correlation, and factor analysis were utilized to test reliability and validity. Receiver operating characteristic (ROC) curve analysis was employed to assess the prognostic utility of the DASI. Results: Participants had a mean DASI score of 39.40 \pm 10.75 and a peak oxygen uptake (Peak VO{}_2) of 19.53 \pm 5.89 mL/min/kg. The Chinese version of the DASI exhibited satisfactory reliability and validity in CVD patients, with a Chronbach’s alpha coefficient of 0.706. The DASI score demonstrated a moderate correlation with Peak VO{}_2 measured by CPET (r = 0.67, p 0.001). Factor analysis yielded three factors, accounting for 56.76% of the total variance, with factor 1 contributing to 26.38% of the variance. ROC curve analysis demonstrated that the DASI exhibited discriminative utility in the identification of patients with improved long-term prognosis (p 0.001). The ROC curve had an area of 0.788 [95% confidence interval (CI) = 0.704–0.871]. The DASI score \ge36.85 served as the optimal threshold for enhanced long-term prognosis, exhibiting a sensitivity of 0.80 and a specificity of 0.69. Conclusions: The culturally adapted DASI questionnaire is a straightforward and efficient tool for reasonably evaluating exercise capacity in Chinese CVD patients.