Abstract: p-Nitrobenzaldehyde,an important intermediate for the manufacture of fine chemicals，was widely used for the preparation of pharmaceutical drugs，dyes, pesticides and non-linear optic materials.p-Nitrobenzaldehyde was prepared indirectly in industrial scale via p-nitrotoluene with chemical oxidants such as potassium permanganate or nitric acid.However such problems as severe environmental pollution, equipment corrosion,and large energy consumption remain to be solved.A novel technology for green synthesis of p-nitrobenzaldehyde by dioxygen oxidation of p-nitrotoluene under mild conditions of 30—50 ℃,0.5—2.0 MPa for 6—12 h was investigated in order to solve above problems.The novel technology was characterized by metalloporphyrin biomimetic catalysts to replace conventional catalysts,with clean oxygen/air replacing chemical oxidants polluting environment,and methanol-NaOH alkali medium replacing corrosive acidic medium.The effects of the center metal ions, substituents and their position, and ligands in axis of catalysts and reaction time on the conversion of p-nitrotoluene, selectivity and yield of p-nitrobenzaldehyde were investigated systematically.The results showed that the conversion of p-nitrotoluene was up to 83.0%,and the maximum selectivity and yield of p-nitrobenzaldehyde were 87.9% and 73.0% respectively under the optimum conditions: methanol as solvent,1.8 mol•L^-1 of NaOH concentration, 6.0×10^-5 mol•L^-1 of T(o-Cl)PPMn catalyst, reaction at 45 ℃, 1.6 MPa for 10h.