The invention provides a Fenton-like catalyst which is chalcopyrite CuFeO2. A preparation method for the Fenton-like catalyst comprises the following steps: dissolving the raw materials ferric nitrate and cupric nitrate in water; adding alkali and a weak reducing agent to prepare a sol; and subjecting the sol to a hydro-thermal reaction so as to prepare the CuFeO2 Fenton-like catalyst. The Fenton-like catalyst provided by the invention has the advantages of simple preparation process, low cost, no organic solvent, environment-friendliness and stable chemical activity; since the particle of the Fenton-like catalyst is micron order, the Fenton-like catalyst can rapidly settle, and thus, the Fenton-like catalyst can be easily recovered and be repeatedly used many times. The Fenton-like catalyst can be used as a natural peroxidase substitute and used for detection and analysis of H2O2 content in food, biological and environmental samples and for degradation and mineralization of organic pollutants.