The invention relates to a feed premix, and particularly relates to the premix for repairing a yellow liver lesion of grass carps, a preparation method of the premix, and applications of the premix. The premix is prepared mainly from the following components in parts by weight: 20-45 parts of corn stigma extract, 5-10 parts of dried orange peel fermentation liquid, 3-8 parts of Chinese wolfberry leaf extract, 15-25 parts of fragrant solomonseal rhizome extract, 10-20 parts of compound active protein powder, and 20-50 parts of soybean meal. Compared with a conventional premix added to a present grass carp feed, the premix provided by the invention is suitable for repairing the yellow liver lesions of the grass carps in different growth stages, and the repairing rate of the yellow liver lesions of the grass carps reaches 100%. Moreover, the premix causes no toxic or side effect for fish bodies, does not destroy the stabilization of a bacterium phase and an algae phase of a culturing water body, and is green and environmentally friendly.