The invention relates to the technical field of photooxidation synthesis, and discloses a simple, convenient and practical visible light synthesis method for quantitatively converting 9, 10-dihydroanthracene into anthraquinone based on molecular oxygen selective oxidation. Under a condition of normal temperature, normal pressure, pure oxygen atmosphere and no catalysts and additives, the synthesismethod can realize 100% raw material conversion and provide a anthraquinone yield of 99.3%, and 86.4% of anthraquinone yield can be obtained even in an air atmosphere. Moreover, the synthesis methodalso shows a good effect on photooxidation of other compounds with structures similar to the structure of 9, 10-dihydroanthracene, and the synthesis method is indicated to have relatively wide applicability. The visible light synthesis method provided by the invention provides a very good example for participation of active O2 of a substrate in selective oxidation, and accords with the concept ofgreen chemistry.