Natural benzaldehyde is one of short-supply international spice. In this paper, several synthetic methods of natural benzaldehyde are reviewed: hydrolysis of Laetrile; synthesis of cinnamon oil and biotransformation of L-phenylalanine. Preparation of natural benzaldehyde from natural cinnamon oil, which is rich in China, is introduced in detail, including oxidation, alkaline hydrolysis and NCW (near-critical water) method, with a view to provide guided information for increasing the added value of natural cinnamon oil.