The dipeptide sweetener N-[3-(3-Hydroxy-4-methoxyphenyl)propyl]-α-L-aspartyl-β-cyclohexyl-L-alanine-1-methyleste (III) was synthesized from 3-(3-hydroxy-4-methoxyphenyl)propanal (II) and a dipeptide (I) via a reductive amination reaction under an overall yield of 50%. The intermediate viz. 3-(3-hydroxy-4-methoxyphenyl)propanal (II) was prepared via a Witting reaction followed by a hydrogenation and a DIBAL-H reduction; while the dipeptide (I) was synthesized via a condensation of 3-cyclohexyl-L-alanine and Boc-L-aspartic acid-4-benzyl ester. The structure of product (III) was confirmed by IR, 1HNMR, 13CNMR and HRMS spectroscopic methods, and its sweetness was verified to be about 25000 times than sucrose. The optimum reaction conditions for the synthesis of product (III) were determined as follows: n(II):n(I)=1:1, the loading of Pd/C catalyst is 10% of the total weight of the reaction material in 80% methanol, the preferred reaction temperature was 40 ℃, and reaction time was 20 h.