The invention relates to a high-efficiency coal-saving combustion-supporting additive, which comprises the following compositions in weight percentage: 2 to 5 percent of dicyclopentadienyl iron, 4 to 8 percent of palladium chloride, 8 to 12 percent of cerium oxide, 13 to 16 percent of surfactant, 10 to 18 percent of detonator, 12 to 18 percent of combustion promoter, 15 to 22 percent of sulphur-fixing agent, and the balance being water. The method for preparing the high-efficiency coal-saving combustion-supporting additive comprises the steps that: a catalyst, the sulfur-fixing agent, the detonator, the combustion promoter, the surfactant and the water are added according to the proportion and are stirred evenly to obtain the high-efficiency coal-saving combustion-supporting additive. The high-efficiency coal-saving combustion-supporting additive has no corrosiveness, is safe and steady under normal temperature and normal pressure, ensures that bunker coal is completely combusted, improves thermal efficiency, saves energy sources, reduces the emission of harmful gas such as sulfur dioxide and so on simultaneously, has simple preparation technology, and reduces production cost.