Food allergy is an important social health problem in children’s nutrition. The incidence of food allergy in children is increasing year by year, and it can cause multiple organ system involvement, most commonly gastrointestinal, skin mucosal and respiratory symptoms. The most common symptoms are gastrointestinal, skin mucosal and respiratory symptoms. Infants and young children are a special susceptible group. Common manifestations of food allergic reactions: 1. Digestive system: nausea, diarrhea, bloody stools, constipation, abdominal distension, severe abdominal pain, bad breath, hiccups, flatulence. 2, skin system: eczema, urticaria, dry skin, dark circles under the eyes, external genital edema, itching. 3.Respiratory system: breath-holding, chest tightness, irritating cough, dyspnea, running watery nose. 4.Nervous system: irritability, irritable, fidgety, inattentive. 5, audio-visual system: blurred vision, puffy eyelids, conjunctival congestion, tearing, hearing loss, slurred speech. Common foods that cause allergies are: milk, wheat flour, eggs, chocolate, beans, shellfish and so on. In addition food additives can also cause allergic reactions, such as monosodium glutamate (monosodium glutamate) can cause rubella, yellow foods can cause asthma, and benzoate can cause hives. Individuals have great differences in food sensitivity, some infants are very sensitive to beans, shellfish and other foods, even if eating a very small amount of food, can also cause a violent reaction, manifested as violent urticaria. Some infants are allergic to certain foods only when they eat too much of them, while moderate amounts of food do not cause allergic problems. The 3 major risk factors for food allergy in children are: 1. Family history of allergic diseases: children of parents with various allergic disease manifestations have a high incidence of food allergy. 2, skin symptoms: eczema, erythematous air masses and itching in early infancy are associated with allergic diseases. The incidence of food allergy in children with allergic skin diseases is as high as 90%. 3, too early to add complementary foods: 4 months to add complementary foods in infants and young children allergy risk is 1.35 times the late addition of complementary foods. It is recommended that the addition of solid foods should be delayed until after 6 months of age, especially animal foods, and avoid adding peanuts and soybeans too early to infant foods. Prevention of food allergy should start from the following points: 1, implementation of breastfeeding: only breastfeeding can satisfy all the nutrition of infants within 6 months, and can greatly reduce the incidence of allergies. Therefore, for infants with allergies, breastfeeding time should be adhered to until the spontaneous disappearance of the infant’s food allergy, that is, at 10-12 months. 2.Scientific addition of complementary foods: babies from 4 months to add complementary foods, should first add rice flour food, as well as vegetables and fruits. Infants 6-7 months, gradually add fish, meat, meat, in preparation for the weaning period, to reasonable nutrition instead of breast milk, to ensure nutritional balance. After the process of adding food to infants, they should go through the process of trial feeding-adapting and liking, and then switch to the trial feeding of new food, so as to find out whether the infants have any food allergies and to reduce the adverse consequences brought by blindness. At the same time, the trial amount of new food should be small at first, about 5-10 ml, mainly to observe whether the infant has any allergy, and then gradually increase the amount of food to 30-40 ml. However, it is important not to feed too much of the same food at one time, as overfeeding of a single food is also a cause of food allergy. It should be emphasized that excessive sugar, fat, chemical additives, salt and monosodium glutamate (MSG) are harmful to infants. Therefore, babies should never add salt and MSG to complementary foods, and should try to use foods high in potassium and low in sodium as nutritional supplements for babies. Treatment: Avoiding allergic foods is the only effective way. Milk protein allergy is common in small infants. If the infant is breastfed, under the premise of strict avoidance of allergic foods, the mother should eat fully hydrolyzed formula and deeply hydrolyzed formula (mixed feeding), and gradually transition to moderately hydrolyzed and ordinary formula depending on the alleviation of allergic symptoms.