Objective To investigate the improvement of trait coping style after group cognitivebehavioral therapy (GCBT) and the effect of trait coping styles on GCBT in patients with mild depression.Methods The depressive symptom，anxiety symptom and trait coping style of mild depression patients be-fore and after GCBT and during follow-up were compared in this prospective self-control study. Results One hundred and two patients with mild depression were recruited. Compared to baseline，the scores of depression symptom，anxiety symptom and trait coping style at 12 weeks，24 weeks，36 weeks and 48 weeks declined sig-nificantly (P ＜0.05). Logistic regression analysis showed that baseline anxiety symptom，negative coping style，and attendance rate entered the final equation. Conclusions GCBT can significantly improve depression symp-tom，anxiety symptom and trait coping style. And the efficacy can last for a long time for mild depression patients. Baseline anxiety symptom，negative coping style，and attendance rate have significant influence on GCBT.