2-year-old baby crying in the middle of the night is mainly paroxysmal abdominal pain, calcium or vitamin D deficiency, physiological reasons. 1. paroxysmal abdominal pain: for 2-year-old babies, if indigestion or ascariasis and other problems, it is easy to appear in the middle of the night paroxysmal abdominal pain symptoms, so it will produce the performance of the middle of the night crying, and is not easy to pacify, easy to be accompanied by profuse sweating and other symptoms. 2. lack of calcium or vitamin D: 2-year-old baby body is in the peak growth and development, the demand for nutrition is relatively large, if there is a lack of calcium or vitamin D phenomenon, so there will be crying in the middle of the night along with the problem of abnormal bone development. 3. Physiological reasons: 2-year-old baby if the daytime over-excited or frightened, easy to produce sleep disorders, thus triggering the performance of midnight crying. If a 2-year-old baby sleeps in the middle of the night with hunger, it is also easy to cry. 2-year-old baby crying in the middle of the night may also have other causes, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.