Osteoporosis but normal blood calcium usually requires calcium supplementation. Osteoporosis is the loss of bone mass due to a variety of reasons, thus causing the patient’s bone density and bone quality to decline, at this time, the bones are deficient in calcium, easy to fracture. Normal blood calcium indicates that the calcium ions in the blood are normal, but normal blood calcium is not equal to normal calcium in the bones. When the calcium intake is insufficient or too much is lost, under the regulation of various hormones, the calcium in the bones will be released into the blood in order to keep the blood calcium in the normal range, but at this time, the loss of calcium in the bones occurs. Therefore, calcium supplementation should not be based only on the blood calcium level, but should be based on the patient’s bone density, blood calcium and other conditions to make a comprehensive judgment to avoid adverse effects.