The invention provides a preparation method for a carbon cloth electrode based on cobalt phosphide/hemoglobin modification. The preparation method comprises the following steps: dissolving cobalt nitrate, ammonium fluoride and urea into a mixed aqueous solution; soaking a carbon cloth into the mixed aqueous solution; reacting under a heating state, and drying to obtain a former body of cobalt phosphide/carbon cloth; putting the former body of cobalt phosphide/carbon cloth and sodium hydrogen phosphate at the two ends of a porcelain boat; heating in a tubular furnace filled with nitrogen, thereby obtaining the carbon cloth/cobalt phosphide; coating a layer of hemoglobin solution on the surface of the electrode of the carbon cloth/cobalt phosphide, and cold-drying to obtain the carbon cloth with hemoglobin modification; rinsing the surface of the carbon cloth with hemoglobin modification, thereby obtaining the carbon cloth based on cobalt phosphide/hemoglobin modification; and lastly, using a thin aluminum sheet as an electric lead contact surface to prepare the carbon cloth electrode based on cobalt phosphide/hemoglobin modification. The electrode can be used for detecting H2O2, the response time is short, the sensitivity is high, the detecting linear scope of H2O2 is from 2my m-2670my m and the electrode is reusable.