3-Substituted-1,2-benzisoxazole derivative of the following formula: ##SPC1##Wherein R.sub.1 is hydrogen, hydroxy, nitro, alkyl, alkoxy, halogen or amino; R.sub.2 is hydroxyamino, amino, hydrazino, mono- or di- alkyl substituted amino, aralkylamino, acyloxyamino, morpholino, piperazine which is unsubstituted or substituted with alkyl, aralkyl or aryl at 4 position, or pyrrolidino, or R.sub.2 may combine with imino group and form together with the adjacent carbon atom a heterocyclic ring such as imidazoline or tetrahydropyrimidine; and n is an integer of 0 to 3, and its pharmaceutically acceptable acid addition salt, and preparation thereof. The present compounds show valuable pharmacological properties, such as anti-reserpine activity, central nervous depressing activity, anti-hypertensive activity and l-dopa potentiating activity.