Fenton advanced oxidation technology is widely used in the treatment of refractory organic wastewater. Because it produces strong oxidizing OH (hydroxyl radical), which can rapidly oxidize and decompose the complex organic pollutant molecules, so its application is wide. The efficiency of Fenton oxidation mainly depends on the yield of �·OH (hydroxyl radical). The more and higher concentration, the higher removal rate of organic pollutants. According to the theory of free radical pairs,free radicals are always emerge in pairs.In some cases free radicals recombine,which reduces OH and reduces reaction efficiency. The recombination can only occur between "singlet state" free radical pairs.When there is no "singlet state" free radical that it cannot recombine,free radical reaction can only performed outside the cage. With the effect of an external magnetic field, the probability of the single state form is less,and the radical pair recombination is less. This facilitates higher reaction efficiency. We modified Fenton reagent technology by using the reaction in a certain strength magnetic field. 1. Reaction rate is doubled.Magnetized Fenton reagent advanced oxidation technology emerges higher rate .OH.The reaction is faster,HRT is shorter,and equipment footprint is smaller. 2. Higher COD removal rate.Magnetic Fenton reaction has 10% more COD removal rate. 3. Less chemical consumption.Magnetic field can reduce the recombination of free radicals,which indirectly reduces chemical consumption. 4. After sewage is magnetized, the physical and chemical properties will change to a certain extent,such as pH,viscosity,diffusion coefficient, surface tension,electrical conductivity, etc., which can affect the process of dissolution, crystallization, polymerization, wetting,agglomeration, solidification, and precipitation. And the metabolic processes of biological systems also have effect.Magnetic field also has an obvious memory effect on water.It changes the physical and chemical properties of the sewage and weakens the cage effect of the solution, which facilitates the out-of-cage reaction reduces the probability of recombination of free radicals, and also facilitates the smooth progress of the reaction.