A facile and efficient procedure has been developed systematically for the oxidative cleavage of cinnamaldehyde to benzaldehyde by sodium hypochlorite with water as the only solvent in the presence of beta-cyclodextrin (abbreviated as beta-CD). Different factors influencing cinnamaldehyde oxidation e.g. reaction temperature, the amount of catalyst and oxidant, have been investigated. The yield of benzaldehyde reaches 76% under the optimum conditions (333 K, 4 h, molar ratio of cinnamaldehyde to beta-CD is 1 : 1). Furthermore, a feasible reaction mechanism including the formation of benzaldehyde and the two main byproducts (phenylacetaldehyde and epoxide of cinnamaldehyde) has been proposed.