The invention discloses 1-butyl-2-hydroxyl aralkyl piperazine derivatives and their use as antidepressants. The derivatives of the present invention have triple inhibition effect on the reuptake of 5-HT, NA and DA, and can be administrated to the patients in need thereof in form of composition by route of oral administration, injection and the like. Compared with clinically currently used dual targets antidepressants (such as venlafaxine), said derivatives may have stronger antidepression effect, broader indications, faster onset and lower neurotoxicity and side reaction; and said derivatives have stronger antidepression activity, lower toxicity, higher bioavailability, longer half life and better druggablity, compared with aryl alkanol piperazine derivatives and optical isomers thereof disclosed in prior art. The 1-butyl-2-hydroxyl aralkyl piperazine derivative is the free alkali or its salt of a compound of formula below: