Abstract: This study aimed at investigating the correlations between antidepressive effect of valproate and improvements of NET and 5-HTT expression in depressive rats leaded by chronic mild unpredicted stress(CUMS)with solitary condition. Sixty male SD rats were divided into normal group(NG), model group(MG), valproate treated-normal group(VNG), and valproate treated-model group(VMG), randomly. The changes of depressive behaviors were evaluated by the open-field test and force swimming test. The contents of MDA, activities of SOD and CAT in serum, the mRNA and protein expression of NET, 5-HTT in hippocampus were determined by biochemical methods, Real-time PCR and Western Blot, respectively. Results showed that CUMS can significantly decrease the activities in open-field test, SOD and CAT activities in serum, expression of 5-HTT in hippocampus, and obviously increase the immobility time in force swimming test, the level of MDA and expression of NET. The treatment of valproate obviously improved the changes induced by CUMS. However, the treatment of valproate had no significant influences on behaviors of NG rats. So, it revealed that improvements of the mRNA and protein expression of NET, 5-HTT may be involved in the antidepressive effect of valproate.