NOVELTY - The (2S)-2-benzylsuccinic acid and acetic anhydride are reacted to obtain (3S)-3-benzyldihydrofuran-2,5-dione. The (3S)-3-benzyldihydrofuran-2,5-dione and (3aR,7aS)-octahydro-1H-isoindole are reacted under nitrogen atmosphere to obtain (2S)-2-benzyl-4-((3aR,7aS)-octahydro-2H-isoindol-2-yl)-4-oxobutanoic acid. The (2S)-2-benzyl-4-((3aR,7aS)-octahydro-2H-isoindol-2-yl)-4-oxobutanoic acid, sodium hydroxide and calcium chloride are reacted to obtain mitiglinide calcium.    USE - Preparation of mitiglinide calcium used for treating type II diabetes mellitus.    ADVANTAGE - The method enables economical preparation of mitiglinide calcium with high yield and reduced usage amount of palladium/carbon catalyst, without environmental pollution.    DETAILED DESCRIPTION - Dimethyl succinate, benzaldehyde and sodium methoxide are reacted to obtain dimethyl (2E)-2-benzylidenesuccinate. The dimethyl (2E)-2-benzylidenesuccinate, hydrogen chloride and sodium hydroxide are reacted to obtain (2E)-2-benzylidenesuccinic acid using methanol as solvent. The molar ratio of dimethyl succinate, benzaldehyde and sodium methoxide is 1:0.5:0.7. The (2E)-2-benzylidenesuccinic acid is reduced in presence of hydrogen and palladium/carbon catalyst, to obtain 2-benzylsuccinic acid. 2-Benzylsuccinic acid and (1R)-1-phenylethanamine are reacted, to obtain bis(1-phenylethan-1-aminium)-(2E)-2-(phenylmethylidene)butanedioate. The bis(1-phenylethan-1-aminium)-(2E)-2-(phenylmethylidene)butanedioate, hydrogen chloride and sodium hydroxide are reacted, to obtain (2S)-2-benzylsuccinic acid. The (2S)-2-benzylsuccinic acid and acetic anhydride in mass ratio of 1:1 are reacted to obtain (3S)-3-benzyldihydrofuran-2,5-dione. The (3S)-3-benzyldihydrofuran-2,5-dione and (3aR,7aS)-octahydro-1H-isoindole are reacted under nitrogen atmosphere to obtain (2S)-2-benzyl-4-((3aR,7aS)-octahydro-2H-isoindol-2-yl)-4-oxobutanoic acid. The (2S)-2-benzyl-4-((3aR,7aS)-octahydro-2H-isoindol-2-yl)-4-oxobutanoic acid, sodium hydroxide and calcium chloride are reacted to obtain mitiglinide calcium.