Decreased bone density of localized thoracic vertebrae may be related to disuse atrophy, osteoporosis, bone tuberculosis, etc. It is necessary to clarify the etiology and target treatment. 1. Disuse atrophy: it is especially seen after fracture, due to the limitation of activity, long time inactivity, resulting in the reduction of bone mass, X-ray examination often suggests that the bone density is reduced. 2. Osteoporosis: mostly seen in elderly patients, especially in postmenopausal women, due to a substantial decline in estrogen levels in the body, resulting in bone loss, and then osteoporosis, leading to the examination suggests that the local thoracic vertebrae bone density is reduced. 3. Bone tuberculosis: this is a relatively common clinical orthopedic diseases, tuberculosis can be detected through the tuberculin test the presence of tuberculosis, there will also be a decrease in bone density imaging manifestations, clinically, may also be accompanied by low-grade fever, fatigue and other symptoms. In conclusion, we should pay attention to regular checkups, and if there are any abnormal symptoms, go to the orthopedic department or spinal surgery department as soon as possible, complete the relevant examinations, make a clear diagnosis, and standardize the treatment according to the doctor’s instructions.