2-(1,3-Dioxane-2-yl)-6-methoxyphenol (Ⅲ) was synthesized by 2-hydroxy-3-methoxy benzaldehyde (Ⅰ) with acetalation. 3-(2- (1, 3-Dioxane-2–yl)-6-methoxy) phenoxyl benzaldehyde (Ⅴ) was synthesized by reaction of compounds Ⅲ and 3-bromobenzaldehyde (Ⅳ). Structure characterization of the target compound Ⅴ was made based on 1H-NMR and MS. By changing reaction condition, the optimum reaction conditions for compounds Ⅴ were found as follows: n(Ⅲ): n(Ⅳ): n(K2CO3): n(CuCl) = 1: 1.05: 2: 0.3. Reaction time and yield was 5h and 68.8% respectively under reflux condition, the purity was 98.7％.