Self-measurement of bone density is through the patient’s self-feeling to initially determine whether there is a decrease in bone density, the patient if the density decreases or osteoporosis will appear when the phenomenon of sleepy legs, joint pain, and some patients may also appear leg cramps and other uncomfortable symptoms, this situation should be promptly to the hospital for examination, a clear diagnosis. In the hospital, the initial diagnosis can be made by taking a picture, and if there is serious osteoporosis, the diagnosis can also be made by taking a picture. In addition, bone density can be examined in the hospital by professional instruments, including two kinds, one is dual-energy X-ray bone density examiner, and the other is to diagnose the bone density condition by ultrasonic examination. Although ultrasonic examination has the advantages of low cost and no radiation to people, the result of this examination is not very accurate, and it is better to use dual-energy X-ray bone densitometer to examine and judge the bone density in the clinic.