Depressive disorder is one of the serious mental diseases， and its mechanism involves psychological， physiological and social aspects. Early life stress caused by traumatic events is a major risk factor for depression. Studies have shown that patients with depression exhibit telomere shortening， which may be related to the occurrence of depression， especially with exposure to early traumatic events. This paper describes the relationship between early traumatic events and telomere length and depression， and reviews the related mechanisms of early traumatic events affecting telomere length， so as to explore the genetic and pathological mechanisms related to the two， and provide important clinical reference significance for the prevention and treatment of depression.