The invention discloses a method for synthesizing (S)-2-hydroxy-2'-(3-phenylureaphenyl)-1,1'-binaphthyl-3-formaldehyde, which uses widely available raw materials, makes operation easy, has high yield and produces little pollution. The method comprises the following process steps: dissolving 3-formoxyl-1,1'-binaphthol serving as a raw material in methanol, cooling in an ice bath, adding sodium borohydride, and reducing to obtain 3-hydroxymethyl-1,1'-binaphthol; dissolving 3-hydroxymethyl-1,1'-binaphthol in acetone serving as a solvent, adding 2,2'-dimethoxypropane to perform a reaction in the presence of a catalyst, extracting with an organic solvent, and obtaining (S)-2-hydroxy-1-(2,2-dimethyl-1,3-dioxo-1,2,3,4-tetrahydroanthracene-9-)-naphthalene by column chromatograpic separation; dissolving (S)-2-hydroxy-1-(2,2-dimethyl-1,3-dioxo-1,2,3,4-tetrahydroanthracene-9-)-naphthalene in dry dimethyl formamide (DMF) serving as a solvent, adding sodium hydride under an ice bath condition, reacting for 0.5 and 1 hours, adding 3-(4-methoxyphenyl)-ureido-benzyl bromide, reacting and obtaining (S)-2-(3-phenylureidobenzoxy)-1-(2,2-dimethyl-1,3-dioxo-1,2,3,4-tetrahydroanthracene-9-)- naphthalene by column chromatograpic separation; dissolving the (S)-2-(3-phenylureidobenzoxy)-1-(2,2-dimethyl-1,3-dioxo-1,2,3,4-tetrahydroanthracene-9-)- naphthalene in glycol serving as a solvent, heating to remove a protective group under the action of p-toluenesulfonic acid and reacting to obtain (S)-2-hydroxy-3-hydroxymethyl-2'-(3-tetrahydroanthracene)-1,1'-binaphthyl; and finally, oxidizing the (S)-2-hydroxy-3-hydroxymethyl-2'-(3-tetrahydroanthracene)-1,1'-binaphthyl in dry dichloromethane by pyridinium chlorochromate, and after reaction, filtering the reaction product by kieselguhr, concentrating and performing column chromatograpic separation to obtain the target product.