The invention provides a method for preparing a deuterated aromatic organic compound. The method comprises the following steps: firstly, dissolving a halogenated aromatic compound and an alkali metal salt MA into a deuterated solvent or a mixed solvent of the deuterated solvent and a common solvent, dropping an organic silicon reagent, performing stirring reaction at minus 40 DEG C to 150 DEG C, and performing separation purification after reaction, thereby obtaining the deuterated aromatic organic compound. By adopting the method, the deuterated aromatic organic compound can be efficiently, economically and environment-friendly prepared without participation of a transition metal or a metallic tin reagent, and the deuteration rate of the prepared deuterated product is greater than 95%. The method is gentle in condition, good in substrate universality and high in yield, and the prepared deuterated compound can be widely applied to fields of medicine chemistry and organic chemistry.