NOVELTY - A carbon-supported platinum-based electrocatalyst preparation method involves mixing XC-72 carbon powder and acetone solution, and filtering the mixture. The filter cake is added into nitric acid and hydrogen peroxide solution. The obtained solution is filtered, and ground to obtain carbon powder. A complexing agent is added into reductant to obtain dissolved solution. Solution containing precursor is dropped into the dissolved solution. The powder is added into the solution. The solution is placed into an oven, heated, and cooled. The obtained product is ground to obtain solid powder.    USE - Method for preparing carbon-supported platinum-based electrocatalyst of fuel battery by microwave organic sol.    ADVANTAGE - The method enables preparing the carbon-supported platinum-based electrocatalyst in a simple, quick and inexpensive manner. The electrocatalyst contains small granular sized active elements, and has high activity. The electrocatalyst can be highly dispersed on carbon carrier and mass produced.    DETAILED DESCRIPTION - A carbon-supported platinum-based electrocatalyst preparation method involves mixing XC-72 carbon powder and acetone solution on mass ratio of 1:30-1:50 at room temperature, and agitating the mixture. The mixture is filtrated. The filter cake is washed cleanly by de-ionised water, and dried in vacuum. The dried filter cake is added into mixed solution of nitric acid and hydrogen peroxide on volume ratio of 2:1-5:1. The obtained solution is refluxed for 8-12 hours at 70-90 degrees C to obtain refluxed reaction solution. The reaction solution is filtered. The obtained filtered cake is washed by the deionised water till the filtered cake is neutral. The filtered cake is dried in vacuum, cooled and ground to obtain preprocessed carbon powder. A complexing agent is added into alcohol reductant, and agitated sufficiently to obtain dissolved solution, where the complexing agent is sodium citrate, citric acid, tartaric acid, sodium tartrate or ethylene diamine tetraacetic acid and the alcohol reductant is ethylene glycol, glycerin or propylene glycol. Solution containing noble metal precursor is dropped into the dissolved solution, and agitated to obtain solution, where noble metal in the precursor occupies 20-60% of total mass of platinum/carbon electrocatalyst and the precursor is chloroplatinic acid hexahydrate, ruthenium (III) chloride and palladium (II) chloride. The carbon powder is added into the solution, and agitated to obtain another mixed solution, where molar ratio of the carbon powder to the noble metal in the latter mixed solution is 1:0.015-1:0.086. Potassium hydroxide-alcohol solution or sodium hydroxide-alcohol solution are added into the latter mixed solution. PH of the latter mixed solution is adjusted to be 8-10. The latter mixed solution is placed into a microwave oven, and heated by microwave. Power of the oven is adjusted to 400-1000W. The latter mixed solution is heated for 50 seconds to 20 minutes to obtain another reaction solution. The latter reaction solution is cooled to room temperature. PH of the latter reaction solution is adjusted to be 3-5. The latter reaction solution is crushed into sol, and infiltrated. The obtained product is washed by the de-ionised water till chlorine ion is removed from the washed wastewater. The product is dried in vacuum, cooled and ground to obtain solid powder. The solid powder is thermally processed and activated to finally obtain platinum /carbon electrocatalyst.