The invention discloses a preparation method of rotigotine, and belongs to the technical field of medicine synthesis. According to the method, 5-methoxy-2-tetralone is used as a raw material for amination, asymmetric reduction, halogenation and methoxyl group removal four step reaction for synthesis of chiral rotigotine {(-)-(S)-2-(N-propyl-N-(2-(2-thiophene) ethyl] amino]-5-hydroxy-1, 2, 3, 4-tetralin}. According to the method, a simplex stereoscopic structural compound is synthesized by stereo selective chemical reaction, in the asymmetric reduction process, hantzsch ester 1, 4-dihydropyridine (HEH) is used as a reducing agent, and chiral phosphoric acid is used as a catalyst to synthesize an important intermediate (S)-2-(N-n-propyl) amido-5-methoxy tetralin (II) with a simplex stereoscopic structure, the use of a chiral reagent for splitting to obtain the simplex stereoscopic structural compound is avoided, the synthesis procedure is shortened, the yield is improveds, and the method is favorable for industrialized production.