Cinnamyl alcohol can be biotranformed into natural 2-phenylethanol with the endophytic strain Sphingomonas sp.Z45. To improve the conversion yield of cinnamyl alcohol and the concentration of 2-PE, the biotransformation conditions in organic solvent-water biphase system were investigated. Oleic acid was selected as the organic phase of the biphase system. 1 mL seed liquid was inoculated in 10 mL fermentation medium and cultured for 24 h, and then 10 mL oleic acid and 3 g/L cinnamyl alcohol were added. The reactions were performed at 30 ℃ and 200 r/min for 12 h, the conversion of cinnamyl alcohol reached 88%, and the final concentration of 2-phenylethyl alcohol was 2.64 g/L. Compared with the result of the mono-aqueous system reaction under the same conditions（the amount of cinnamyl alcohol added was 3.0 g/L), the conversion yield of cinnamyl alcohol and the concentration of 2-phenylethanol were increased by 88% and 120% respectively.