Breastmilk contains nutrients of high biological value that can be easily utilized by infants. In addition to carbohydrates, proteins and energy suitable for infant absorption, breast milk also contains irreplaceable immune components and growth regulating factors. Breastmilk is divided into colostrum, which is expressed within six days after delivery, and mature breastmilk, which is expressed after six days after delivery. Breastmilk is classified differently and stored for different times. Colostrum can be stored at room temperature between 27℃ and 32℃ for 12 hours. Mature breastmilk can be kept at room temperature around 15℃ for 24 hours. It can be kept at room temperature around 19℃-22℃ for 10 hours. It can be kept in room temperature around 25℃ for 6 hours. And it can be kept in a refrigerated room at 0℃-4℃ for 8 days. In the freezer, it can be kept for 3-4 months. Breast milk should be stored in clean containers, such as sterilized bottles and sterilized milk storage bags. For short-term storage you can choose to put it directly in the bottle, but if long-term frozen storage is needed, use a milk storage bag. It is recommended that mothers sterilize their nipples, hands or breast pump before expressing milk to avoid contamination of milk. It is recommended not to heat breast milk by microwave or boiling to avoid destroying the nutrients in breast milk, but to heat it back to temperature under water. Breastfeeding should be contraindicated if the mother is infected with HIV or suffers from serious diseases, such as chronic nephritis, diabetes, malignant tumor, mental illness and other conditions.