Benzaldehyde was synthesized by indirect electro oxidation of toluene with Mn(Ⅲ) as medium.Uniform design method was used to study the effects of concentration of reactants,cell voltage,reaction temperature and reaction time on the yield and current efficiency of Mn(Ⅲ).The optimum technical conditions were found by using multiple regression analysis based on the data obtained from our experiments.Electrolyte including Mn(Ⅲ) was added into the vessel and toluene was oxidized to benzaldehyde.The efficacy of the medium that was recycled for many times was tested.