An improved process for the preparation of Butorphanol tartrate of formula (I), comprising the steps of: (a) obtaining a compound of formula (IV) by reacting a compound of formula (II) with a compound of formula (III) in suitable conditions; (b) resolving a compound of formula (IV) to obtain a mixture of compound of formula (IVa) and (IVb) using a suitable resolving agent in a suitable solvent to further obtain a mixture of compound of formula (IVc) and (IVd); (c) protecting a compound of formula (IVc) with di-tert-butyl dicarbonate in presence of a suitable base in a suitable solvent to get a compound of formula (V); (d) obtaining a mixture of compound of formula (VIa) and (VIb) by the epoxidation of compound of formula (V) with peroxy acid in a suitable solvent; (e) obtaining a mixture of compound of formula (VIIa) and (VIIb) by acid catalyzed ring opening and deprotection of mixture of compounds of formula (VIa) and (VIb) with a suitable acid in a suitable organic solvent; (f) obtaining a mixture of compound of formula (VIIIa) and (VIIIb) by reacting a mixture of compound of formula (VIIa) and (VIIb) with cyclobutylmethyl bromide in presence of a suitable base in a suitable solvent; (g) cyclizing a mixture of compound of formula (VIIIa) and (VIIIb) with borane in presence of an anhydrous acid with or without suitable organic solvent to obtain a compound of formula (IX); (h) demethylating a compound of formula (IX) using a suitable demethylating agent in a suitable solvent to obtain Butorphanol of formula (X); and (i) obtaining Butorphanol tartrate salt of formula (I) from Butorphanol of formula (X) by using tartaric acid in a suitable organic solvent. (a) obtaining a compound of formula (IV) by reacting a compound of formula (II) with a compound of formula (III) in suitable conditions; (b) resolving a compound of formula (IV) to obtain a mixture of compound of formula (IVa) and (IVb) using a suitable resolving agent in a suitable solvent to further obtain a mixture of compound of formula (IVc) and (IVd); (c) protecting a compound of formula (IVc) with di-tert-butyl dicarbonate in presence of a suitable base in a suitable solvent to get a compound of formula (V); (d) obtaining a mixture of compound of formula (VIa) and (VIb) by the epoxidation of compound of formula (V) with peroxy acid in a suitable solvent; (e) obtaining a mixture of compound of formula (VIIa) and (VIIb) by acid catalyzed ring opening and deprotection of mixture of compounds of formula (VIa) and (VIb) with a suitable acid in a suitable organic solvent; (f) obtaining a mixture of compound of formula (VIIIa) and (VIIIb) by reacting a mixture of compound of formula (VIIa) and (VIIb) with cyclobutylmethyl bromide in presence of a suitable base in a suitable solvent; (g) cyclizing a mixture of compound of formula (VIIIa) and (VIIIb) with borane in presence of an anhydrous acid with or without suitable organic solvent to obtain a compound of formula (IX); (h) demethylating a compound of formula (IX) using a suitable demethylating agent in a suitable solvent to obtain Butorphanol of formula (X); and (i) obtaining Butorphanol tartrate salt of formula (I) from Butorphanol of formula (X) by using tartaric acid in a suitable organic solvent. <EOS>