The invention relates to a magnetic remediation material for organic matter pollution in soil or water, and preparation as well as application thereof. Preparation comprises the following steps of (1) preprocessing clay mineral, including drying, smashing and sieving; (2) adding the sieved clay mineral into a molysite solution, and adding other metal salts, heating up the mixed turbid liquid to 30-90 DEG C and continuously stirring for 0.5-5 hours to make the liquid steady, adding alkali liquor to increase the pH value of the solution to 8-11, and stirring continuously for 0.5-2 hours; (3) separating, drying and smashing solid sediment, and executing thermal treatment, thereby obtaining the magnetic remediation material capable of magnetically separating the organic matter pollution in soil or water. As compared with the prior art, the remediation material provided by the invention has magnetic separability, can be recycled for cycle use, also has relatively high stability and catalytic activity, as well as good ecological compatibility, and is suitable for in-situ or ex-situ remediation of soil or water polluted by polycyclic aromatic hydrocarbon, polychlorinated biphenyl, Dioxin, organo-chlorine pesticides, and the like, and degradation intermediate products thereof.