The method in accordance with the present invention has: mixing E2M, an organic solvent, a weak base, sodium dithionite, and a phase transfer catalyst to obtain an E2M mixture solution; heating the E2M mixture solution and adding water to obtain a heated E2M aqueous solution having an organic layer; and extracting the organic layer from the heated E2M aqueous solution, and condensing and drying the organic layer to obtain donepezil. Employing sodium dithionite as a reducing agent improves safety over hydrogen gas used in conventional methods and lowers the cost in contrast to the conventional noble metal catalysts that are extremely expensive. Furthermore, the method of the present invention requires only 60 minutes of reaction time to synthesize donepezil with a promising yield more than 85%, which greatly raises the efficiency and economic value of the manufacture of donepezil.