Children crying in the middle of the night may be related to the daytime fright, lack of vitamin D, indigestion and so on. 1. Frightened during the day: some children are frightened by accidents during the day, or too excited to play during the day, resulting in sudden waking up in the middle of the night to find no familiar people, so they cry in the middle of the night. 2. Vitamin D deficiency: rickets caused by lack of vitamin D and calcium. There may be crying at night, accompanied by frequent waking at night, excessive sweating, occipital baldness, square skull, funnel chest, rib ectropion and other symptoms. 3. Indigestion: As a result of small indigestion, the food is not digested in time, causing abdominal distension, which can lead to children crying in the middle of the night. Children crying in the middle of the night may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.