Written emotional expression is a kind of writing to express one’s emotion and thought according to some special topics within a certain time. Evidences have supported that written emotional expression can enhance individuals’ ability to cope with stressful life events. The theory study of early traditional psychotherapy was mainly focused on the language of thoughts and feelings. However, the studies in which writing about traumatic events may improve individuals’ psychological and physiological health begin to emerge. In this paper, a comprehensive literature review was made with regard to written emotional expression at home and abroad, and then the definition, research paradigm, relevant theories and impact factors were introduced. At last, it put forward the limitations about this field and the direction in the future.