The large head circumference of the baby is not necessarily caused by calcium deficiency, there are many reasons for the large head circumference: 1, familial large head, the child is normal except for the large head circumference, the normal large head is related to the large head circumference of both parents or a single parent; 2, vitamin D deficiency rickets active children show a square skull, head circumference is also larger than normal children, often at the same time there are other clinical manifestations, such as night terrors, excessive sweating, occipital baldness, rib cage, etc. The child may have other clinical manifestations such as night terrors, excessive sweating, occipital baldness, and rib exostosis. The diagnosis can be made based on the etiology, clinical manifestations, serum, vitamin D, calcium, phosphorus, alkaline phosphatase, and skeletal X-ray examination. The head circumference is large. In addition to this, there is also a combination of special facial features, with or without mental retardation. For children with large head circumference, mothers and fathers must take their children for regular medical checkups to monitor their head circumference, fontanelle, intelligence level and physical growth and development, and go to the hospital in time to confirm the diagnosis if abnormalities are found.