The present invention relates to a multifunctional pet food and a preparation method thereof. The multifunctional pet food can provide eight nutrient substances required by brain development, improvesmental activity of dogs, and has effects of benefiting brain and helping memory. By supplementing elements with stress reaction resistance and oxidation resistance, the multifunctional pet food effectively reduces damages of stress reaction on pets, plays effects of calming nerves and relieving tension emotions, can promote rapid proliferation of taste bud cells of tongue mucosa, regulates appetite, inhibits certain harmful bacteria in intestinal tracts, improves secretion functions of a digestive system and activity of enzymes in histiocytes, and finally plays effects in regulating intestines and stomach to help digestion. In conclusion, under synergistic effects of the raw materials, the multifunctional pet food has multiple effects of delaying memory decline, enhancing learning ability, relieving and relaxing stress reaction resistance, refreshing breath, improving intestinal health, protecting joints, helping sports, promoting development of puppies, etc.