The invention discloses a method for preparing 3, 4-dihydroxyphenethyl alcohol through bio-enzyme catalysis, which comprises the following steps: by taking escherichia coli fermentation liquor for inducing enzyme production as a raw material, centrifuging to obtain thalli, adding a buffer solution to suspend the thalli, introducing oxygen and the like, and adding a substrate p-hydroxyphenethyl alcohol and bio-enzyme catalysis to react to obtain the 3, 4-dihydroxyphenethyl alcohol. According to the method, the 3, 4-dihydroxyphenethyl alcohol is obtained through biological enzyme catalysis and biological synthesis by taking the p-hydroxyphenethyl alcohol as a substrate, the reaction condition is mild, no by-product is generated, and the residual quantity of the substrate is small; the catalytic efficiency of the biological enzyme is high and reaches 99%, and the yield of the product 3, 4-dihydroxyphenethyl alcohol reaches 13 g / L or above; the preparation method is green, environment-friendly and short in reaction period, can be applied to large-scale industrial production, and meets market requirements.