The invention concretely relates to a preparation method and an application of an active carbon supported nanometer Fe-Al (hydr)oxide particle composite material. The preparation method comprises the following steps: dissolving a salt containing trivalent ions Fe<3+> and a salt containing trivalent ions Al<3+> in deionized water to form a mixed salt solution A; preparing boiling deionized water, and continuously heating the boiling deionized water; dropwise adding the mixed salt solution A into the boiling deionized water to form a solution B, and controlling the pH value of the solution B to be 5-7.5; and continuously heating the solution B to form a brown Fe-Al (hydr)oxide sol solution C, cooling the brown Fe-Al (hydr)oxide sol solution C to room temperature, pouring away the obtained supernatant, and adding a certain mass of active carbon to the sol solution C to form a sol and active carbon mixture D. Iron and aluminum salts form nano-particles and are highly-efficiently and uniformly loaded on the active carbon through a fierce method. The method has the advantages of cheap and easily available materials, simple device, convenience in operation, and easiness in control of a result.