Abstract: The photoelectro-reactors were introduced from two types of slurry photoelectro-reactor and immobile photoelectro-reactor. An effective way of modifying photo-electrode by deposition of metal and coupling of semiconductor used to improve the oxidation efficiency of immobile photoelectro–reactor was pointed out. The main factors, including light source, material, additional applied potential, solution condition and reaction atmosphere, which affected the efficiency of photoelectro-reactor were discussed. Besides, some proposals for further studies of photoelectro-reactor were presented.