NOVELTY - (S)-Dimethyl-cyclopropylmethyl carboxylate and catalyst in mass ratio of 0.01-0.09:1 are mixed, alcoholic solution of ammonia is added, ammonolysis reaction is carried out at 25-120 degrees C for 24-30 hours and the resultant reaction mixture is sequentially subjected to desolvation and extraction processes, to obtain (S)-2,2-dimethyl-cyclopropylmethyl formamide. The (S)-2,2-dimethyl-cyclopropylmethyl formamide is purified using alcohol or mixed solution of alcohol and acid, and crystallized, to obtain chiral dimethyl-cyclopropylmethyl formamide having purity of more than 99.5%.    USE - Preparation of chiral dimethyl-cyclopropylmethyl formamide (claimed).    ADVANTAGE - The method efficiently provides chiral dimethyl-cyclopropylmethyl formamide, by simple and environmentally-friendly process.    DETAILED DESCRIPTION - Chiral catalyst is added into a reactor, halogenated hydrocarbon solvent, isobutylene and diazoacetate are added, cyclopropanation reaction is carried out at (-25)-25 degrees C for 2-3 hours, and the resultant reaction mixture is sequentially subjected to pickling, acid and alkali washing and distillation processes, to obtain (S)-dimethyl-cyclopropylmethyl carboxylate. The obtained (S)-dimethyl-cyclopropylmethyl carboxylate and catalyst in mass ratio of 0.01-0.09:1 are mixed, alcoholic solution of ammonia is added, ammonolysis reaction is carried out at 25-120 degrees C for 24-30 hours and the resultant reaction mixture is sequentially subjected to desolvation and extraction processes, to obtain (S)-2,2-dimethyl-cyclopropylmethyl formamide. The obtained (S)-2,2-dimethyl-cyclopropylmethyl formamide is purified using alcohol or mixed solution of alcohol and acid, and crystallized, to obtain chiral dimethyl-cyclopropylmethyl formamide having purity of more than 99.5% and enantiomeric excess value of more than 99.5%. The molar ratio of isobutylene and diazoacetate is 0.8-1.2:0.8-1.2. The addition amount of chiral catalyst is 0.5-3 %mass. The volume ratio of halogenated hydrocarbon solvent and isobutylene is 1-3:1.