Depression is a psychological disorder characterized by behavioral， neurochemical and other physiological abnormities． Chronic exposure to mild unpredictable stress( CUMS) has previously been found to cause an antidepressant-reversible decrease in the consumption of palatable sweet solutions， at the same time biochemical disturbances induced by the CUMS procedure were similar to those found in human depression． We review the pathological changes of the animal model of depression ( CUMS ) ． it reflected in some persistent molecular pathologys，such as the changes in receptor ，signal transduction．