Abstract: In order to find a green oxidation process of p-nitrotoluene, its oxidative reaction by oxygen in alkaline liquid system catalyzed by cobalt-tetracarboxylphthalocynine, which was deposited on activated carbon black, has been studied in this paper. It was found that cobalt-tetracarboxylphthalocynine loaded on activated carbon black was more active than that unloaded, meanwhile the bigger the specific surface of activated carbon black is, the more the activity of the catalyst is. The highest yield of p-nitrobenzoic acid was 87.6% when the reaction temperature was 55℃ and the oxygen pressure was 2.0 MPa. This process has advantage of simple operation and easy separation of product.