A 4-year-old baby crying in the middle of the night is not necessarily caused by psychological problems, but may also be caused by a lack of trace elements or organic diseases that cause physical discomfort. Parents need to observe whether the child has other abnormalities and deal with them according to different causes and symptoms. Common causes and treatment methods a. Psychological factors: children are frightened or traumatized, can appear in the middle of the night crying situation, parents should be soothed, give the child a sense of security, if the situation is serious can consult a psychologist. Second, living habits: Some parents will see the baby wake up in the middle of the night and judge that the baby is hungry, so they feed the child, resulting in the child to develop the habit of waking up at night to drink milk, so there is often crying at night. Parents should use scientific methods to help their children quit night milk, and the symptoms of crying in the middle of the night will disappear. Third, disease factors: 1, lack of vitamins or trace elements: If the baby lacks vitamins or calcium, it will lead to poor closure of fontanelle, resulting in long-term excitement of the plant nerves and brain, unable to sleep quietly, or crying in the middle of the night. Parents should give their children appropriate vitamins, calcium tablets or dairy products suitable for infants and children, and more sunshine to promote the absorption of calcium elements; 2. Other: If the child has intestinal inflammation, appendicitis, or the contents of the gastroduodenum reflux into the mouth when lying down, so that the baby appears discomfort, and therefore will cry in the middle of the night. Parents should actively ask their babies if they are unwell, and if they are unwell, they need to go to the hospital in time for symptomatic treatment. The child’s crying at night must not be generalized, but should be searched for foreign stimuli that produce pain, such as foreign objects that sting the child in the blanket, clothing that is too tight, etc. It is necessary to communicate with the child in a timely manner, and if necessary, take the child to the hospital for examination.