Children crying in the middle of the night may be caused by physiological factors, or due to vitamin D deficiency, parasitic infections and other pathological factors. 1. Physiological factors: when the child in the middle of the night because of hunger or environmental temperature is too high, too low, noise, etc. may appear children sleep in the middle of the night crying phenomenon, remove the triggers can be improved. 2. Vitamin D deficiency: usually leads to difficulty in falling asleep, night terrors, excessive sweating, occipital baldness, and later bone deformation. It can also cause children to cry in the middle of the night. 3. Parasitic infections: easy to attack the child’s stomach and intestines at night, resulting in discomfort, some parasites such as pinworms will crawl out of the anus, resulting in perianal itching, can cause the child to sleep in the middle of the night crying. Children sleep to the middle of the night crying, there are other reasons, it is recommended to timely medical care, to identify the cause, if necessary, with the doctor treatment.