Osteoporosis is a metabolic bone disease characterized by decreased bone mass and structural damage of bone tissue, and its causes include increased bone resorption, decreased bone formation, decreased bone quality and poor lifestyle. 1. Increased bone resorption: lack of estrogen and lack of vitamin D in postmenopausal women can enhance the function of osteoclasts, accelerate bone loss and increase bone resorption, which makes osteoporosis easy to occur. 2. Decrease in bone formation: Calcium is an important mineral for bone formation. During the growth and development of bone or when the calcium requirement increases, calcium deficiency will lead to a decrease in bone formation. Adolescent bone formation is also related to peak bone mass, which is mainly determined by heredity. When sexual maturation is impaired, peak bone mass decreases, leading to decreased bone formation. 3. Decreased bone quality: Bone quality, including bone morphology, mineralization, and biological properties, is genetically related. Decreased bone quality leads to increased bone fragility and fracture risk. 4. Poor lifestyle: Poor lifestyle such as smoking, alcoholism, low physical activity, and picky eating are risk factors for osteoporosis, which can affect bone formation and resorption. In addition to the above reasons, diseases such as hyperthyroidism, Cushing’s syndrome, and drugs such as phenytoin sodium, phenobarbital and carbamazepine may cause osteoporosis. It is recommended that patients with osteoporosis under the guidance of a doctor should undergo a complete examination to identify the cause of the disease and then undergo targeted management and treatment.