The baby sleep half sleep suddenly cry may be frightened or disease factors (vitamin D deficiency, indigestion) and other reasons. 1. frightened: the child’s nervous system is not yet fully developed, easily disturbed by external factors, in sleep suddenly frightened or nightmares will wake up halfway to sleep and cry. 2. Disease factors: lack of vitamin D or calcium and other nutrients will lead to increased nerve excitability, difficult to fall asleep, easy to wake up after sleep. Suffering from upper respiratory tract infections, indigestion, intestinal inflammation and other diseases that cause discomfort when the baby falls asleep, will also appear to sleep half asleep suddenly crying symptoms. The baby sleep half suddenly cry, there are other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, to give targeted treatment or standardized treatment.