In this study, we translated and localized the Adult Decision‐making Competence scale (A‐DMC) and tested its reliability and validity with large samples. Results show the Chinese A‐DMC has relatively good reliability (Cronbach's alpha above 0.6 and test–retest reliability coefficients ranging from 0.44 to 0.78 on all subscales), comparable with the original version. Regarding validity, results of exploratory factor analysis and confirmatory factor analysis support the one‐factor model, indicating the A‐DMC has good internal consistency and construct validity. A‐DMC scores correlated positively with cognitive ability, constructive decision‐making styles, and good decision outcomes. Additionally, individuals with higher A‐DMC scores were found to perform better on the Cambridge gambling task and Iowa gambling task. These results confirm the validity of the Chinese version of the A‐DMC, which is suitable for measuring decision‐making competence in Chinese adults.