The invention covers the usage of 20(S)-protopanaxadiol in the formulation of medicaments for treating depressive affective disorders. The pharmacological test results indicated that the compound could significantly elevate the level of NE, 5-HT and HAV in the brains of model rats and obviously improve 5-HTP-induced tremor and LD-induced behavior, and inhibit the reuptake of 5-HT and NA.