Abstract: Objective: To explore the effect of social support on depression of left behind elderly in rural areas, and to test the mediating role of trait coping style. Methods: 321 left behind elderly in rural areas were surveyed with social support revalued scale, geriatric depression scale-30, and trait coping style questionnaire.Results: (1) The detection rate of depression of left behind elderly in rural areas is relatively high.(2) Social support was positively correlated with positive coping style and was negatively correlated with negative coping style and depression,positive coping style was negatively correlated with depression, negative coping style was positively correlated with depression. (3) Mediation modeling indicated there were three paths that social support affected depression:the first one is that social support directly affected depression; the second one is that social support affected depression through mediating effect of positive coping style; the third one is that social support affected depression through mediating effect of negative coping style.Conclusion: The depression of left behind elderly in rural areas is more prominent, which is closely correlated with social support and coping style, coping style exert multiple mediating effects on the relationship between social support and depression.