Bone density testing is a common method to determine if a person has osteoporosis, or if their bone mass is normal. Dual-energy x-ray bone densitometry is commonly used in clinical practice and -2.5 SD is used as a comparison value. If the BMD is below -2.5 SD, the patient has osteoporosis. If the BMD is between -1SD and -2.5SD, there is bone loss and preventive treatment for osteoporosis is also needed. If the BMD is greater than -1SD, the bone mass is normal. The common sites for measuring bone density are the spine and hip, because the spine and hip are prone to the earliest bone loss, and some hospitals use the wrist as the site of bone density measurement. A proper or perfect bone density measurement should be done in multiple parts to check the bone density of each part, and the bone density should be measured at the same time in 3 parts: wrist, spine and hip. Once osteoporosis occurs, anti-osteoporosis treatment should be carried out as early as possible. In addition to basic calcium and osteotriol treatment, bisphosphonates, calcitonin and even osteogenic drugs should be applied to treat osteoporosis.