The baby sleeps and cries all the time may be caused by physiological factors such as bad mood, environment, etc. It may also be caused by gastrointestinal disorders, calcium deficiency and other diseases, as well as other diseases such as colds and flu. 1. Physiological factors: if the child is mentally stimulated during the day, nervousness, panic and other adverse emotions, will lead to the phenomenon of the child always crying in his sleep. In addition, the environment in which the child sleeps may be too hot and stuffy, which may also cause the child to cry in his sleep. 2. Gastrointestinal dysfunction: The cause of gastrointestinal dysfunction is complex, and is considered to be caused by physiological and psychological factors. The main symptoms are postprandial fullness, epigastric pain, diarrhea and other symptoms, if the child has abdominal pain and other uncomfortable symptoms, will always cry in bed. 3. Calcium deficiency: If the child is chronically deficient in calcium, it will lead to a decrease in blood calcium in the child’s body, which will lead to excitation of the brain and the autonomic nerves, and also lead to the patient’s constant crying during sleep. 4. Other: colds, cerebral palsy and other diseases can also lead to the phenomenon of crying in bed. Babies crying in their sleep may be caused by physiological factors and do not need special treatment. If it is caused by a disease, parents should take the child to the doctor immediately and follow the doctor’s instructions.