To provide a method for synthesizing an anthraquinone, economically and simply in view of a production technology, not having a defect in a method publicly known by a preceding technology, starting from 1,4-naphthoquinone and 1,3-diene and capable of being executed in an industrial scale, especially capable of avoiding a risk of forming an explosive gas mixture in an oxidation process.

This method for producing an anthraquinone of general formula I (R1 to R4 are each same or different and hydrogen, an 1-8C alkyl, or 2-8C alkenyl), is provided by reacting 1,4-naphthquinone, with 1,3-diene of formula II (R1 to R4 are each same as described above) in a cyclizing addition process to form corresponding tetrahydroanthraquinone, and then reacting the tetrahydroanthraquinone with oxygen in the presence of a basic catalyst in an oxidation process to form the anthraquinone. The cyclizing addition process and the oxidation process are both performed in the presence of an aqueous diluent.