The invention discloses a (R)-styrene glycol preparation method that utilizes site-directed mutagenesis to alter coenzyme specificity and stereoselectivity, belongs to the technical field of biocatalytic asymmetric transformation, and provides a recombinant Escherichia coli strain BL21 / pETSCR6768 with the preservation CCTCC NO of M208079, and an asymmetric transforming preparation method of (R)-styrene glycol. The preparation method leads Ser in position 67 and His in position 68 of a (S)-specific carbonyl reductase to mutate to Asp, constructs recombinant plasmid pETSCR6768, and feeds the Escherichia coli, thus obtaining the recombinant strain E.coli BL21 / pETSCR6768 which leads the coenzyme specificity of (S)-specific carbonyl reductase to change from NADPH to NADH; furthermore, the stereoselectivity of the product is altered from (S)-styrene glycol to (R)-styrene glycol, and the preparation method provides an effective way for preparing (R)-styrene glycol in high efficiency and low cost and has significant meaning for recognizing the stereoselectivity of functional zymoprotein in the molecule and protein level.