Objective Major Depression(MD) is a heterogeneous disease and the precise aetiology is still unknown.The neuronal plasticity disorder is now considered to be one of the depression causes.Animal experiments indicated that the neuronal plasticity can affect the occurrence of depression and development by Notch signal pathway.The objectives of this study is to analysis the expression of Notch signal pathway in peripheral blood with Depression,to explore the effects of Notch signal pathway and Depression interaction at the molecular level.