Two-year-old babies cry when they are not moving, may be some physiological phenomena, may also be the manifestation of certain diseases, such as vitamin D deficiency, intestinal cramps, etc., should be timely consultation to identify the cause of the disease. 1. Physiological factors: two-year-old babies may not be able to fully express their thoughts and behavior, so they will not move to cry to express themselves; may also be the baby’s insecurity, through the way of crying to attract the attention of the surrounding people and care. 2. Pathologic factors: (1) Vitamin D deficiency refers to vitamin D in the body by various factors, insufficient intake, insufficient production, poor conversion and utilization, resulting in a series of physiological abnormalities, causing a variety of clinical manifestations; the affected children will appear irritable, sleep disturbance, night terrors, excessive sweating and other symptoms, can be shaking the head and rubbing the pillow leading to occipital baldness. (2) Two-year-old babies may express their physical discomfort through crying, such as abdominal pain of varying degrees during an attack of intestinal spasms, and in severe cases, the child may show crying, rolling, cold sweating, pallor, or accompanied by vomiting. There are more reasons for children to cry frequently, and other factors cannot be ruled out. Parents are advised to bring their children to the doctor in a timely manner if physiological causes are ruled out, so that the doctor can clarify the causes and provide targeted treatment.