Disclosed is a method for preparing an iodinated aromatic compound. More specifically, disclosed is a method of preparing an iodinated aromatic compound by iodinating an aromatic compound in the presence of oxygen over a zeolite catalyst, in which the aromatic compound and its monoiodo compound, as raw materials, are allowed to react with iodine. In comparison with a method in which only the aromatic compound is used as a raw material without adding the monoiodo compound, the disclosed method can increase the productivity of diiodo compounds and the selectivity to a p-diiodo compound and, at the same time, suppress side reactions, thus lengthening the life span of the catalyst.