The invention discloses a preparation method of a Cu-Fe bimetal complexing type magnetic chitosan carbon aerogel catalyst applied to wet oxidation, and belongs to the field of environmental functionalmaterials. Chitosan carbon is used as a carrier, CuO, Cu2O, Fe3O4 and FeO are used as main active components, and the complex catalyst is prepared. According to the preparation of the catalyst, Cu-Fecomplexing type sol is prepared by utilizing the complexing action between chitosan molecules and metal ions. The preparation method comprises dropwise adding the sol into a sodium hydroxide solution, carrying out deprotonation and solidification to form small balls, washing with water, freezing, freeze-drying and calcining to prepare the magnetic aerogel catalyst. The catalyst prepared in the invention has a large specific surface area, the carrier and the metal active component are combined through complexation, the disadvantages of low loading component and easy dissolution of traditionalimpregnation methods are avoided, and the catalyst can be recovered by using an external magnetic field. When the catalyst is used for wet oxidation treatment of landfill leachate nanofiltration concentrate, it is found that the removal effect on humic acid and fulvic acid is good, and the COD removal rate can reach 74.6%-86.8%.