The invention discloses an earthworm powder growth promoter for pork pigs and a preparation method thereof. The growth promoter is prepared by mixing earthworm meal, folium cortex eucommiae leaf powder and propolis powder according to the weight ratio of 1:1:0.5. The preparation method comprises the following steps: collecting Taiping No. 2 earthworms, putting the collected Taiping No. 2 earthworms under the sun for insolation for 2-5 days, then baking in a drying box, crushing, screening by a 40-mesh sieve, and preserving in a dry drafty place by sealing tightly for standby use; collecting cortex eucommiae leaves in July and August, deactivating enzymes and then baking in a drying box, crushing, screening by the 40-mesh sieve, and preserving in the dry drafty place by sealing tightly for standby use; baking propolis purchased from the markets in the drying box at 65 DEG C, crushing, screening by the 40-mesh sieve, and preserving in the dry drafty place by sealing tightly for standby use; and mixing uniformly the prepared earthworm powder, the cortex eucommiae leaf powder and the propolis powder according to the weight ratio of 1:1:0.5.