NOVELTY - Preparing cinacalcet hydrochloride comprises: e.g. (a) reacting 1-(naphthalen-1-yl)ethanone with a chiral reagent and reducing to obtain (R)-2-methyl-N-((R)-1-(naphthalen-1-yl)ethyl)propane-2-sulfinamide (I); (b) reacting (I) with a 3-halo-propyne compound to obtain (R)-2-methyl-N-((R)-1-(naphthalen-1-yl)ethyl)-N-(prop-2-ynyl)propane-2-sulfinamide (II); (c) reacting (II) with 1-halo-3-(trifluoromethyl)benzene compound to obtain (R)-2-methyl-N-((R)-1-(naphthalen-1-yl)ethyl)-N-(3-(3-(trifluoromethyl)phenyl)prop-2-ynyl)propane-2-sulfinamide (III); and (d) reducing (III) in presence of a catalyst.    USE - The method is useful for preparing cinacalcet hydrochloride.    ADVANTAGE - The method: has good selectivity and short preparation steps; provides the chiral product with high yield and high optical purity; is safe, simple, economical and suitable for large scale industrial production; reduces environmental pollution; and utilizes low cost and easily available raw materials.    DETAILED DESCRIPTION - Preparing cinacalcet hydrochloride comprises: (a) dissolving 1-(naphthalen-1-yl)ethanone in a solvent (8-12 ml/g) and reacting with a chiral reagent in the presence of isopropyl titanate at 20-200 degrees C, reducing by sodium borohydride to obtain (R)-2-methyl-N-((R)-1-(naphthalen-1-yl)ethyl)propane-2-sulfinamide (I), where the molar ratio of the chiral reagent and 1-(naphthalen-1-yl)ethanone is 1:1-2:1, the molar ratio of isopropyl titanate and 1-(naphthalen-1-yl)ethanone is 0.5:1-2:1, and the molar ratio of sodium borohydride and 1-(naphthalen-1-yl)ethanone is 1:1-2:1; (b) dissolving (I) in a solvent (8-12 ml/g) and alkalizing at 0-100 degrees C by an alkali having equivalent weight of 1-2, reacting with a 3-halo-propyne compound to obtain (R)-2-methyl-N-((R)-1-(naphthalen-1-yl)ethyl)-N-(prop-2-ynyl)propane-2-sulfinamide (II), where the molar ratio of 3-halo-propyne and (I) is 1:1-2:1; (c) dissolving (II) in the solvent (8-12 ml/g) at 20-180 degrees C and reacting with 1-halo-3-(trifluoromethyl)benzene compound in the presence of diethylamine and a catalyst to obtain (R)-2-methyl-N-((R)-1-(naphthalen-1-yl)ethyl)-N-(3-(3-(trifluoromethyl)phenyl)prop-2-ynyl)propane-2-sulfinamide (III), where the molar ratio of the 1-halo-3-(trifluoromethyl)benzene and (II) is 0.8:1-2:1, the molar ratio of diethylamine and (II) is 0.8:1-2:1, and the amount of the catalyst added is 0.5-2 molar equivalent weights; and (d) adding (III) into the solvent (8-12 ml/g), reducing by hydrogen in the presence of a catalyst and hydrochloric acid at pressure of 5 kg/cm2 and at 20-200 degrees C to obtain the cinacalcet hydrochloride, where the weight ratio of the catalyst and (III) is 1:4.5-1:5.5 and the molar ratio of hydrochloric acid and (III) is 1:1-2:1.