The invention provides a method for producing a dichloro addition product of an aliphatic olefin by photocatalysis under visible light. The method includes reacting an aliphatic olefin as a substrate with hydrochloric acid as a chlorine source in an organic solvent under visible light irradiation in the presence of copper chloride with visible light absorption ability as a catalyst, to obtain the dichloro addition product of the aliphatic olefin, wherein the reaction is carried out under an oxygen-containing atmosphere, the aliphatic olefin comprises a carbon-carbon double bond and a C9-C15 aliphatic chain connected to the carbon-carbon double bond by a covalent bond. In the invention, visible light is used to provide the energy and a transition metal chloride with visible light absorption ability is used to undergo light-induced electron transfer from chloride with a reaction substrate, thereby initiating an addition reaction to obtain a dichloro addition product.