The invention provides the novel use of 20(S)-protopanaxadiol in the preparation of medicaments for the treatment of depressive psychiatric disorders. The pharmacological test results indicated that the compound could remarkably increase the level of NE, 5-HT and HAV in the brains of model rats having depressive disorders, remarkably enhance tremors induced by 5-hydroxytryptophan (5-HTP) and behavioral effects induced by levodopa, and inhibit the re-uptake of 5-HT and NA.