Baby sleep on his back may be food accumulation, may also be seeking security and respiratory blockage and other causes. 1. Accumulation of food: the baby is in the growth and development period, the spleen and stomach are not yet fully developed, if not fed properly is easy to cause accumulation of food, and accumulation of food will cause bloating, colic and other symptoms, the baby sleeps on his stomach to relieve gastrointestinal symptoms. 2. Seek a sense of security: babies are prone to insecurity, lying down to sleep in a position similar to that of the mother’s womb, will make the baby feel more secure, sleep more sound. 3. Respiratory blockage: baby respiratory tract inflammation or rhinitis, there will be nasal congestion, runny nose and other symptoms, during sleep will be more serious, the baby may sleep on the stomach to relieve the symptoms. Baby sleeping on his back is not necessarily food accumulation, when the baby appears to sleep on his back for a long time and accompanied by physical discomfort, it is recommended to go to the hospital in a timely manner.