Osteoporosis is a serious global health problem, second only to cardiovascular disease. Osteoporosis is the most common metabolic bone disease in the elderly population, characterized by loss of bone mineral density (BMD) and continuous destruction of bone microstructure, especially in postmenopausal women. It gives rise to bone fragility and fracture risk. Moreover, as people grow older, falls frequently occur with high severity, and nearly 35% to 45% of persons aged 65 or older fall at least once a year. Osteoporotic fractures increase mortality, morbidity, chronic pain, and the cost of social care and it decreases the quality of life. Here, investigators plan to perform different exercise interventions such as circuit exercise, aerobic dance and Tai Chi on the community's older adults to evaluate whether exercise intervention could improve the bone mineral density, physical fitness, muscle strength or quality of life.