The invention discloses a green pig feed and a preparation method thereof. The green pig feed comprises the following raw materials: by weight, 50-60 parts of corn, 120-130 parts of corncob, 5-10 parts of middling power, 3-8 parts of wheat bran, 50-60 parts of rice bran, 1-2 parts of shrimp shell powder, 1-2 parts of jujube root, 5-8 parts of poplar leaf, 10-20 parts of corn stalks, 4-8 parts of wheat stalks, 0.1-0.2 part of nidus vespae, 1-2 parts of Chinese wolfberry leaf, 1-2 parts of chrysanthemum, 1-2 parts of amomum tsao-ko, 3-5 parts of vinegar residue, 1-2 parts of zeolite powder, 1-2 parts of sunflower flower disc, 1-2 parts of anoectochilus roxburghii, 1-2 parts of pomegranate leaf, 1-2 parts of chestnut shell, 1-2 parts of wild chrysanthemum, 1-2 parts of red pepper, 2-3 parts of pear leaf, 3-5 parts of hawthorn seeds, 1-2 parts of rehmannia glutinosa leaf and 1-2 parts of catalpa ovate flower. The green pig feed does not contain any antibiotics, but contains Chinese herbal medicine compositions. The green pig feed has the functions of stomach strengthening and digestion promoting, heat clearing and detoxicating and the like, can help to eliminate endotoxin of pigs, keep the pigs in good growth states, and can prevent diseases of the pigs. Because all of the Chinese herbal medicine compositions are commonly used medicines of people, the green pig feed has no toxic and side effects, and can improve the pork quality of the pigs and make pork more suitable for the people to eat.