One year old baby sleeps on his back because of physiological factors, such as personal sleeping habits, lack of security, etc.; also includes pathological factors, such as indigestion, parasitic infections. 1. Physiological factors: due to the one-year-old baby long time to keep sleeping on his back position, has formed a habit, at the same time, the baby lack of security will also sleep on his back, and parents usually not enough love and companionship, the baby’s introverted personality and other factors. 2. Pathological factors: due to a year-old baby suffering from indigestion or parasitic infections in the body, resulting in frequent abdominal discomfort at night, sleeping on the stomach can help the baby to relieve discomfort. A year-old baby sleeping on his back 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.