The invention relates to a photo-reduction method for carrying out degradation on organic halides by using carboxylic acids or carboxylates, and is characterized in that an
ion-pair complex is generated through the interaction between the
carboxylate radicals in micromolecular carboxylic acids or carboxylates and the
halogen bonds of organic halides; the
ion-pair complex produces a new
absorption band in a visible region, then under the
irradiation exciting of a visible
light source, the excited
ion-pair complex has an
electron transfer, the
oxygen atoms in the micromolecular
carboxylate radicals transmit electrons to the
halogen atoms of the organic halides, and after organic or inorganic alkalis are added, the
electron-donating capacity of the
oxygen atoms in the micromolecular
carboxylate radicals is strengthened, so that the
reaction rate can be accelerated; and while receiving electrons, the organic halides extract
hydrogen atoms from a dissolvent, and after carrying out dehalogenation reduction on the organic halides subjected to
hydrogen extraction, an easily-processed low
halide or complete de-halogenated product (the number of
halogen atoms thereof is reduced) is obtained, thereby achieving the purpose of effectively degradating the organic halides. The method provided by the invention can be performed at normal temperature, and can greatly improve the
solar energy utilization ratio without secondary
pollution, therefore, the method has a wide application prospect.