The invention discloses a preparation method of optically pure S-configuration 1, 1-bis- (4-fluorophenyl)-2-propanol. The chemical molecular structural formula of the optically pure S-configuration 1,1-bis- (4-fluorophenyl)-2-propanol is shown as (II). The S-configuration 1, 1-bis-(4-fluorophenyl)- 2-propanol is an important intermediate of a novel picolinamide bactericide, i.e., florypicoxamid,and has a very high economic value. The chemical reaction equation is shown in specification; in the reaction equation, the compound (I) is subjected to homogeneous asymmetric hydrogenation reaction,and the optically pure compound (II) is obtained with high efficiency and high selectivity. In the reaction, the catalyst is a complex of a chiral ligand and transition metal, and the complex can be prepared in advance and can also be matched in situ. The conversion number (TON, turnover number) of the catalyst is as high as 100,000 and the optical purity is as high as 97% ee. Compared with the prior art, the catalyst provided by the invention has the advantages of being high in atom economy, green, pollution-free, easy to industrialize and the like.