The invention discloses topdressing for fostering eucalyptus. The topdressing is used for fertilizing eucalyptus plantation, and is prepared from raw materials of macroelements of nitrogen, phosphorus and potassium, and microelements of calcium, magnesium, silicon, boron, zinc, copper and molybdenum by the processes of crushing, mixing, pelletizing and the like; the topdressing for fostering eucalyptus comprises the following effective components by weight percent: 18-32% of nitrogen, 3-12% of phosphorus pentoxide, 8-22% of potassium oxide, 5-12% of calcium oxide, 1-5% of magnesium oxide, 2-5% of silica, 0.01-1% of boron, 0.01-1% of zinc, 0.01-1% of copper, and 0.001-0.1% of molybdenum. Correspondingly, the invention also discloses a fertilizing method of the topdressing for fostering eucalyptus. By adopting the topdressing, kinds of necessary nutrients for eucalyptus growth can be met, the fast-growing advantages are fully developed, unnecessary waste of fertilizer nutrients can be reduced, the disease resistance, the wind resistance and the cold resistance of the eucalyptus can be enhanced, and scientific fertilization can be achieved.