Waking up easily at night may be related to too much or too little breastfeeding before bedtime, diapers not being changed in time, too much sleep during the day, low calcium, etc. Babies under 6 months old often have not yet formed a circadian sleep rhythm. Parents should not force it. Babies over 6 months old should watch their diapers more closely and change them in time when they sleep. Most babies cry and wake up easily at night because they are hungry or their diapers are wet and the babies feel uncomfortable. Infants should not sleep too long during the day; the less they sleep during the day, the longer infants sleep at night. In addition, infants should be dressed comfortably, the room temperature should be appropriate, and the blankets should be thin and thick, so that infants can sleep longer at night. Low calcium due to vitamin D deficiency can cause babies to wake up easily at night and be irritable. Vitamin D supplementation can be prescribed by the doctor to improve the state of calcium deficiency and prevent babies from waking up in the middle of the night. It is recommended to follow up your baby’s development regularly at the pediatrician’s office, and intervene if necessary.