Bone density measurement methods are generally divided into four types: the first, single-photon absorptiometry, that is, using the principle that the absorption of radioactive substances by bone tissue is proportional to the bone mineral content, using radioactive isotopes as the light source to determine the bone mineral content of human limb bone. The second type, dual-energy X-ray absorptiometry, is a method in which two types of energy, namely low-energy and high-energy photon peaks, are obtained by passing the X-ray tube ball through a certain device, and after such photon peaks penetrate the body, the scanning system sends the received signals to a computer for data processing and derives the bone mineral content. The third, quantitative CT, also known as QCT, QCT can accurately select specific areas for bone measurement, bone mineral density, and can assess the bone mineral density of cortical bone’s and spongy bone’s respectively. The fourth, ultrasonic measurement method, which has attracted widespread attention due to its absence of radiation and more sensitive diagnosis of fractures, can reflect the amount of bone mineral content and bone structure and bone strength by using the speed of sound wave conduction and amplitude attenuation, and the instrument used is ultrasonic bone densitometer.