The invention relates to a method for preparing a piglet growth-promotion additive. The piglet growth-promotion additive comprises the following materials by weight percentage: 10 to 20 percent of bone meal, 8 to 13 percent of medicated leaven, 8 to 13 percent of anemone, 8 to 13 percent of radix astragali, 8 to 13 percent of radix-polygoni multiflori, 8 to 13 percent of asket fern, 1 to 2 percent of iodized salt, 3 to 5 percent of safflower, 4 to 10 percent of fish meal, 3 to 6 percent of portulacae, 3 to 6 percent of dried old orange peel, 3 to 5 percent of Jian leaven, 3 to 5 percent of honeysuckle, 1 to 2 percent of fructus schizandrae, and 1 to 2 percent of angelica sinensis. The method comprises the following steps: taking the bone meal, the anemone, the radix astragali, the radix-polygoni multiflori, the asket fern, the iodized salt, the safflower, the fish meal, the portulacae, the dried old orange peel, the Jian leaven, the honeysuckle, the fructus schizandrae and the angelica sinensis in proportion, and putting all the materials into a drying machine, wherein the temperature in the drying machine is controlled to be between 20 and 30 DEG C, the drying time is between 25 and 30 minutes, and the dryness of the dried materials is controlled to be between 85 and 95 percent; taking out the materials and crushing the same into powder in a crusher; and taking out the powder and putting the powder into a container.