A green and efficient method for the selective aerobic oxidation of p-cresol to p-hydroxybenzaldehyde catalyzed by co-catalysts between metalloporphyrins and metal salts was investigated and developed. The relationship between the synergistic catalytic effects and the composition as well as amount of co-catalysts was investigated. Moreover, the influence of different reaction conditions was studied in details. A high p-cresol conversion (>99%) and p-hydroxybenzaldehyde selectivity (83%) were obtained using only 1.125 x 10(-5) mol T(p-CH3O)(PPFeCl)-Cl-III-Co(OAc)(2) used under mild, optimized reaction conditions. A possible mechanism for the reaction was also proposed. This work would be meaningful and instructive for the further researches and applications of co-catalyst system on oxidation of cresols and could give some enlightenment on the selectively catalytic oxidation of the side-chain alkyls of aromatics. (C) 2018 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.