Osteoporosis is a disease of disequilibrium between bone formation and bone loss, and vitamin D is one of the key hormones in the regulation of bone metabolism, the major role of which is to provide the proper micro-environment for bone mineralization. Vitamin D deficiency which has been defined by most experts as circulating 25-hydroxyvitamin D levels of less than 20 ng/mL (50 nmol/L) is widespread all over the world. As shown by the results of recent studies, vitamin D deficiency could increase the risk of low bone mineral density or osteoporosis, muscle disorders, falls, and as a matter of course, fractures due to both osteoporosis and falls. Long-term supplementation of vitamin D and calcium are good prevention measures for osteoporosis, falls and fractures. At the same time, they are essential components of osteoporosis management. Many studies show that sufficient vitamin D intake could increase bone mass, and decrease the risk of falls and fractures.