A method for preparing nicotine. (1) The nicotinic acid alkyl ester and N-methylpyrrolidone are subjected to a condensation reaction, and then added with a strong acid to obtain 4-methylamino-1-(3-pyridine)-butanone hydrochloride. (2) The 4-methylamino-1-(3-pyridine)-butanone hydrochloride is reacted with an amino-protecting reagent to obtain an intermediate (4). (3) A chiral alcohol (5) is obtained through an asymmetric reduction. (4) The chiral alcohol (5) is converted into the nicotine through a two-step reaction.