Vitamin D deficiency rickets is a common disease in children, a chronic nutritional disease, accounting for more than 95% of all rickets. This disease is caused by vitamin D deficiency in children, which leads to abnormal systemic calcium and phosphorus metabolism, so that calcium salts cannot be deposited normally in the growing part of the bones, and eventually bone deformities occur. Its main characteristics are incomplete mineralization of the growing long bone epiphysis or bone tissue, or osteomalacia, which is more common in infants under 2 years old. Although rickets rarely threatens life directly, it is easy to be ignored because of its slow onset. Once obvious symptoms occur, the body's resistance is low and it is easy to develop pneumonia, diarrhea, anemia and other diseases. In recent years, the incidence of severe rickets has decreased year by year, but the incidence of mild and moderate rickets is still high.