The invention provides a preparation method of sucrose-6-benzoate, which comprises the following steps: by using sucrose as a raw material, methyl benzoate as an esterifying reagent and an alkali carbonate as a catalyst, synthesizing sucrose-6-benzoate under vacuum distillation conditions; and by using the polar difference between the sucrose and the sucrose-6-benzoate, adding a low-polarity solvent to precipitate unreacted sucrose, thereby purifying the sucrose-6-benzoate. The method can enhance the yield and purity of the sucrose-6-benzoate and recycle the unreacted sucrose, has the advantages of environment-friendly technique, low facility request and high economical efficiency, provides a new way for synthesizing sucrose-6-benzoate, and is suitable for the demands for large-scale industrial production.