The invention relates to a method for synthesizing an asymmetric diaryl selenide compound. The method comprises the following steps: taking aryl carboxylic acid and diaryl diselenides as reaction materials under oxygen conditions in an organic solvent, and carrying out an oxidative decarboxylation coupling reaction under the combined promotion action of a copper catalyst, a ligand and alkali, thereby obtaining the asymmetric diaryl selenide compound. The method is cheap and highly available in aryl carboxylic acid substrate and copper catalyst, wide in substrate range, simple in reaction conditions and high in product yield and purity, develops a novel synthetic route and method for the asymmetric diaryl selenide compound and has excellent application potential and research value.