The invention discloses special chicken feed and a preparation method thereof, and belongs to the technical field of feed. The special chicken feed is made of raw materials including, by weight, 50-80 parts of corn, 10-20 parts of bean pulp, 15-25 parts of sea grasses, 3-6 parts of shell powder, 2-5 parts of tea leaves, 0.2-0.9 part of salt and 1-5 parts of Chinese herbal medicine residues, wherein the Chinese herbal medicine residues include astragalus residues, dangshen residues, tuckahoe residues, white mulberry root-bark residues, plantain seed residues, white atractylodes rhizome residues, radix sileris residues, licorice residues, angelica residues and dangshen residue mixture with the weight ratio of 1:1:1:1:1:1:1:1:1:1. According to the method, the Chinese herbal medicine residues are sufficiently combined with algae and sea grasses causing seawater pollution, the morbidity of chickens can be reduced, the immunity of the chickens is improved, and waste utilization can be achieved.