Subthreshold depression refers to a kind of depression that the patient has not yet reached major depressive disorder， but has clinically significant depressive symptoms. Subthreshold depression has a high incidence， and its pathological mechanism is still unclear. At present， there is no specific treatment for subthreshold depression. Clinicians mainly apply the methods of treating depression to treat patients with subthreshold depression. Cognitive-behavioral therapy has been proved to be an effective way to treat depression. Meanwhile， a number of research has found that it is also effective in treating subthreshold depression. This paper reviews studies on cognitive-behavioral therapy for subthreshold depression， and summarizes the mechanisms of different approaches for subthreshold depression