Using 3-quinone hydrochloride and benzaldehyde as raw materials, (2S)-benzhydrylquinine-3-one (6) was prepared through aldol condensation, Michael addition, and configuration transformation. The imine formed from compound 6 and benzylamine was reduced by Platinum-carbon catalytic hydrogenation, and then further purified by salting with L -camphorsulfonic acid. And the key intermediate (2S,3S)2-benzhydryl-quinine3-amine (10) was prepared by Palladium-carbon catalytic hydrogenation to remove benzyl group. The crude maropiptan was synthesised by reducing the imine which was formed by compound 10 and 2-methoxy5tert-butylbenzaldehyde. The high-purity maropitant citrateIt was obtained in the mixture of acetone, water and methyl tert-butyl ether after purifing by salt formation with L-camphorsulfonic acid. The synthetic route has been optimized to make the work-up process simple and more suitable for industrial production. The chemical structure of target compound was confirmed by ESI-MS and 1HNMR, and the total yield was 20% and the purity was 99.9% (HPLC).