TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Components: In preparing the catalyst with platinum loaded on the support, the water-soluble salt of a metal having catalytic activity is chloroplatinic acid, the metal hydroxide particles are chloroplatinic hydroxide, and the catalyst with platinum loaded on the support is a platinum/support catalyst. The water-soluble salt of a metal comprises platinum and at least one metal selected from ruthenium, rhodium, molybdenum, osmium, iridium, rhenium, palladium, vanadium, tungsten, cobalt, iron, selenium, nickel, bismuth, tin, chromium, copper, titanium, gold and cerium. The support comprises at least one carbon support(s) selected from Vulcan carbon, carbon nanotube, carbon nanowire, multimodal porous carbon, carbon having a double porous structure and carbon capsule. The support comprises at least one selected from titanium dioxide, silica, aluminum oxide and manganese dioxide, or a composite of at least one selected from titanium dioxide, cesium oxide, molybdenum oxide, silica, aluminum oxide and manganese dioxide bonded to carbon. In the reducing the metal hydroxide particles, at least one reducing agent selected from an aqueous solution of NaSH4, LiSH4, HCHO, HCOOH, CH3OH, CH3CH2OH, HCOONa, N2H4 orAlSH4 and ethylene glycol is used. Preferred Method: Preparing the dispersion solution comprises dissolving urea in water to prepare an aqueous urea solution, dispersing the support in the aqueous urea solution to prepare the dispersion solution of the support and adding chloroplatinic acid to the dispersion solution of the support, and the reducing the metal hydroxide particles comprises adding ethylene glycol to the dispersion solution of the support. Alternatively, preparing the catalyst with platinum loaded on the support comprises: dissolving a water-soluble salt of a metal having catalytic activity and urea in water and dispersing a support to prepare a homogeneous dispersion solution; stirring the resulting dispersion solution at high temperature to deposit metal hydroxide particles on the surface of the support; and reducing the metal hydroxide particles deposited on the support. Preparing the dispersion solution comprises dissolving a water- soluble salt of a metal having catalytic activity and urea in water to prepare a metal-urea solution, dispersing a support in a solvent to prepare a dispersion solution of the support, and mixing the metal-urea solution with the dispersion solution of the support, where sodium hydroxide is added to the dispersion solution of the support to adjust acidity to a specific pH. Preparing the dispersion solution comprises: dissolving a water- soluble salt of a metal having catalytic activity in water to prepare an aqueous metal salt solution; dissolving urea in water to prepare an aqueous urea solution; mixing the aqueous metal salt solution with the aqueous urea solution; and dispersing a support in the mixture of the aqueous metal salt solution and the aqueous urea solution. The method further comprises separating the support with the metal hydroxide particles deposited from the dispersion solution prior to the reducing the metal hydroxide particles. Preferred Parameters: The loading amount of platinum particles on the platinum/support catalyst is 10-80 wt.% and an average particle size is 1-5 nm, and the support is selected from carbon black, carbon nanotube, carbon nanofiber, mesoporous carbon, multimodal porous carbon, multilayer carbon structure or a mixture. The dispersing the support is carried out using ultrasonic wave, the adding chloroplatinic acid to the dispersion solution of the support is performed at 70-110 degrees C and pH 7-11, and the adding ethylene glycol to the dispersion solution of the support is performed using microwave or by a hydrothermal method at 100-140 degrees C. The dispersion solution has an acidity of pH 5-12. In the preparing the dispersion solution, urea is added in an amount of 5-200 equivalents based on moles of the water-soluble salt of the metal. The platinum alloy is loaded in an amount of 5-95 wt.% of the total weight of the catalyst. The stirring the dispersion solution is performed at 60-120 degrees C. In the stirring the dispersion solution, hydroxide ions for depositing the metal hydroxide particles on the surface of the support are produced by hydrolysis of urea. In the stirring the dispersion solution, hydroxide ions for depositing the metal hydroxide particles on the surface of the support are produced from the sodium hydroxide added to the dispersion solution of the support and by hydrolysis of urea. Reducing the metal hydroxide particles is performed at 50-400 degrees C under hydrogen atmosphere. EXAMPLE - No suitable example given.