Abstract: ［Abstract］Objective　To observe the correlation between active vitamin D3 level and sarcopenia development in elderly patients in plateau regions and the changes in the correlation factors for sarcopenia under the invention of active vitamin D3 （Calcitriol， Cal ）， and to observe whether Cal could improve the muscle function. Methods　90 patients were assigned to the normal control （Con） arm， and 120 patients with sarcopenia were assigned to the sarcopenia （Sar） arm to receive different oral doses of Cal as intervention （0.25 ug/d for low dose group including 60 patients and 0.25ug bid for high dose group including 60 patients）. Before and after the intervention， levels of 1，25-(OH)2D3 and the inflammatory factors TNF-α，IL-6， IL-10，and hs-CRP were detected using ELISA; HOMA-IR， BMI， and ASMI were calculated; and walking speed and grip strength were measured to observe the correlation between 1，25-（OH）2D3 level and sarcopenia， the changes in these indicators from before to after intervention， and the efficacy and safety of oral Cal for sarcopenia. Results　Prior to intervention， compared with the Con arm， 1，25-(OH)2D3 level， IL-10 level， ASMI， walking speed and grip strength were significantly reduced（P＜0.01）， and HOMA-IR， IL-6， TNF-α and hs-CRP were significantly elevated（P＜0.01） in both dose groups; intervention with Cal produced significant increases in 1，25-(OH)2D3 and IL-10 levels，significantly improved walking speed and grip strength（P＜0.05）， significant decreases in HOMA-IR，IL-6， TNF-α，and hs-CRP（P＜0.05）， which were more marked with higher dose， but no significant changes in ASMI. From before to after intervention，there were no significant changes in BMI or hepatic/renal function，blood calcium，or blood phosphorus in either group. Conclusions　The development of sarcopenia is associated with reduced 1，25-(OH)2D3 level. Cal can lower the inflammatory factors IL-6， TNF-α，and hs-CRP，and elevate IL-10， providing anti-inflammatory and immunoregulatory actions; improve muscle function and strength；and improve insulin resistance. BMI is irrelevant to the management of sarcopenia. Cal is safe at the oral dose up to 0.5 μg/d.