Osteoporosis is a systemic skeletal disease characterized by a decrease in bone mass, degradation of bone microstructure, increased brittleness of bone and susceptibility to fracture. Osteoporosis has become a common disease that seriously affects the productivity and quality of life of the middle-aged and elderly groups in modern society and cannot be ignored. It is generally believed that osteoporosis occurs in groups over 50 years of age, especially in women, and the proportion of osteoporosis increases with age and changes in hormone levels in the body, and osteoporosis is mainly related to calcium loss in the body. 1998-2006, China completed the world’s largest survey on osteoporosis, and the survey results showed that: 413 million people over 50 years of age, the prevalence of vertebral fractures reached 15 percent, the total prevalence of hip fracture 200/100,000; there are nearly 70 million osteoporosis patients; about 214 million people with low bone mass. In addition, the rate of asymptomatic vertebral fracture in postmenopausal women with long-term application of estrogen is as high as 37%; glucocorticoids (used for the treatment of autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, ankylosing spondylitis, inflammatory myopathy, scleroderma, etc., all accompanied by immune abnormalities) are more destructive to bone and can reduce the activity of osteoblasts and increase the activity of osteoclasts, leading to bone loss and bone It can also reduce intestinal calcium absorption and urinary calcium reabsorption, decrease muscle strength, lead to an increased risk of fracture, and produce induced osteoporosis (GIOP). In the face of the large domestic osteoporosis population, how to apply active vitamin D for scientific and rational treatment has become a hot topic of great concern nowadays. Based on the understanding that the occurrence of osteoporosis is mainly related to the loss of calcium in the body, regular vitamin D combined with calcium is currently recognized as the basic bone health supplement, but the results of medical control studies have shown that regular supplementation with regular vitamin D and calcium has limited effect on the improvement of symptoms and reduction of fracture incidence, and the efficacy of regular vitamin D supplementation of 800 IU/d or 6500 IU/w/day in postmenopausal women. The efficacy of regular vitamin D supplementation in postmenopausal women is not satisfactory, with no significant improvement in bone mineral density and no additional benefit even at high doses. Medical research has confirmed that calcium absorption in the body depends on active vitamin D. Active vitamin D can act directly on the target to play a biologically active role in promoting calcium absorption, regulating bone metabolism, improving muscle strength and balance, as well as other therapeutic effects; ordinary vitamin D undergoes two steps of hydroxylation in the body (hydroxylase is present in the liver, kidneys and many other tissues) and is converted into active vitamin D before it can work. Therefore, active vitamin D is strictly a therapeutic drug and not a nutritional supplement; its clinical use reduces the rate of bone loss, the risk of falls and the incidence of fractures in patients with osteoporosis, and also has a significant therapeutic effect on rickets and osteochondrosis caused by severe vitamin D deficiency. Regular vitamin D, when taken, is highly limited in absorption and also predisposes to hypercalcemia and high urinary calcium in large amounts, whereas active vitamin D avoids such problems. The amount of vitamin D obtained from the outside world through the skin decreases significantly, and the amount of 7-dehydrocholesterol (the raw material for vitamin D) in the body decreases approximately twofold. The ability of the kidneys to convert common vitamin D decreases, and the conversion of active vitamin D decreases significantly. However, judging from the physiological point of view: the liver has a huge reserve function for 25-hydroxylase, which does not affect alfazocalciferol hydroxylation and avoids the problem of insufficient conversion of vitamin D due to low renal function. There are currently two types of active vitamin D, one is alfazocalciferol and the other is osteotriol. Alfazocalciferol plasma peak concentrations have no significant peaks and troughs, plasma concentrations remain stable for a longer period of time, and the incidence of high urinary calcium is low during use. Alfazocalciferol can play a multifaceted therapeutic role in glucocorticoid-induced osteoporosis (GIOP), effectively counteracting the pathogenesis of GIOP, increasing calcium absorption, increasing bone mineralization and bone repair capacity, and enhancing muscle strength. Alfazinol has positive immunomodulatory effects on cellular immunity, humoral immunity, and receptor defense, which can improve the condition of autoimmune diseases. Therefore, in addition to its effect on secondary osteoporosis, alfazinol also has therapeutic effects on primary autoimmune diseases, which can yield additional benefits. Alfacalcidol is particularly suitable for the elderly, renal insufficiency, and high-risk groups in the prevention and treatment of primary and secondary osteoporosis, and is now a cornerstone drug in the treatment of osteoporosis. The new edition of the American College of Rheumatology (ACR) guidelines recommend that plasma 25(OH)D concentrations of 30–60 ng/ml and alfacalcidol dosages of 0.5–1.0 μg/d need to be achieved when supplementing with vitamin D; the guidelines require that when starting When receiving supplemental hormone therapy, it is necessary to supplement with both alfacalcidol and calcium in order to prevent bone loss; it is emphasized that the use of hormones should be in small doses and short courses, and it is recommended that anyone using hormones, regardless of the duration and dose, should combine vitamin D and calcium supplementation in order to achieve improved bone density; the higher the vitamin D dose, the lower the fracture incidence.