The invention discloses cow feed and a preparation method thereof. The feed comprises alfalfa hay, pumpkins, rice straw, corn stalks, wheat straw, soya bean meal, rice bran, green stalks, maize germ meal, cottonseed meal, wheat bran, wheat middlings, sunflower seeds, DDGS, whole cottonseeds, carrot, choline chloride, potassium iodide, beer brewer grains, citric acid, magnesium sulfate, tricalcium phosphate, sodium selenite, cod-liver oil, salt, vitamin premix and microelement premix. The preparation method includes a breaking step, a blending step and a pelletizing step. The cow feed and the preparation method thereof have the advantages that the feed has the effects of benefiting qi, nourishing blood and promoting lactation, qi and blood deficiency type cow postpartum hypogalactia can be treated, breast plumpness and normal nipple development can further be promoted, milk is full, and the immunity of cows is improved; moreover, normal grow of cow mammary glands and other body organs can be well guaranteed; the cure rate is high, the feed becomes effective quickly, the course of treatment is short and no toxic and side effects exist.