The metabolic syndrome(MS)is a pathological state in children and adolescents,which is mainly characterized by aggregation onset of overweight or obesity,hyperinsulinemia or insulin resistance,im-paired glucose tolerance or type 2 diabetes,hypertension,lipid metabolism disorder and atherosclerosis.The prev-alence rate of MS has increased year by year.Studies have confirmed that the risk factors of coronary heart dis-ease and other chronic diseases in adults and its pathological process existed in childhood,so it will be of great significance to early detection and prevention of chronic diseases.At present,many reports have showed that CD40-CD40L system is closely related to cardiovascular disease,diabetes and many kinds of risk factors of car-diovascular disease,diabetes mellitus.It also plays a very important role in the development and prognosis of dia-betes.In this paper,the research progress of the relationship between CD40-CD40L system and metabolic syn-drome is reviewed.Monitoring CD40-CD40L system may be helpful to early diagnose and further therapy.It'll provide a new approach for the diagnosis of metabolic syndrome,so as to better control the incidence of related chronic diseases.