Children crying in the middle of the night, for various reasons, there can be physiological reasons, can also be seen in pathological factors, the common causes are summarized as follows: 1, the child is not comfortable: the child crying in the middle of the night is a manifestation of the sense of discomfort, the common situation are: (1) overfed and overfed. Eat too much or eat too little, waking up more at night, can not meet the demand or relieve discomfort in time, the child will be easy to cry at night; (2) abdominal discomfort: indigestion, intestinal flatulence; (3) urination and defecation; (4) clothing is too tight, wrapped in thick blankets, the indoor temperature is too high, the air is dry; (5) teething; (6) growing pains; (2) the state of the disease: children are sick after a change in temperament, the mother’s sense of dependence, easy to appear irritable in the middle of the night, and the child’s sense of security. Enhanced, easy to appear irritable, crying in the middle of the night. Especially seen in febrile illnesses, such as respiratory infections, otitis media, gastroenteritis, colic, dehydration and so on. In small infants embodied especially obvious. 3.Vitamin D/calcium deficiency: Children may have restless sleep at night, sweating and night sweating, wet hands and feet, shaking head back and forth, crying at night, etc. This condition is most common. This situation is the most common. 4, alternating deep and light sleep or pediatric night terrors: during light sleep or night terrors, children are prone to nighttime crying, and can be awakened or not awakened when crying. For pediatric sleep reversal, night milk dependence, weaning period, other factors such as mosquito bites, eczema and other factors can induce the child to appear at night sleep is not stable, crying.