Background/objectivesAdults with attention-deficit/hyperactivity disorder (ADHD) have more maladaptive cognitions, emotional problems and a poorer quality of life (QoL). A verification of the psychological model in clinical samples is needed for a better understanding of the mechanisms of ADHD diagnosis on QoL via maladaptive cognitions, emotional symptoms, and their interactions.Methods299 ADHD participants and 122 healthy controls were recruited. ADHD core symptoms, maladaptive cognitions, emotional symptoms and psychological QoL were rated. Pearson’s correlation and structural equation modeling were analyzed to explore the relationship and influence of ADHD diagnosis on QoL.ResultsMore maladaptive cognitions, emotional symptoms, and poorer QoL were found in the ADHD group, and the dysfunctional attitudes were on par between ADHD with or without medication (p = 0.368). Moderate to strong correlations were found between emotional symptoms, maladaptive cognitions and QoL, and ADHD core symptoms presented correlations among the above scores (r = 0.157 ~ 0.416, p