Objective To investigate the correlation of serum 25 (OH) D, fall risk and muscle strength with vitamin D deficiency in elderly osteoporosis. Methods 126 elderly patients with osteoporosis admitted to Department of Orthopedics in our hospital from February 2016 to March 2018 were selected and assessed by various tests, including Chair Rising Test (CRT). The normal gait velocity test (NGV), Timed Up and Go Test (TUGT), and handheld dynamometry (HHD). Meanwhile, the serum levels of 25 (OH) D and blood calcium were detected. The correlation of serum 25 (OH) D, fall risk and muscle strength with vitamin D deficiency was analyzed. Results In terms of age, patients with higher age had lower levels of 25 (OH) D (P＜0.05), smaller the muscle strength and the higher risks of falling (P＜0.05). After age correction, the level of 25 (OH) D and muscle strength were increased gradually, and the risk of fall was decreased gradually (P＜0.05). Pearson correlation analysis showed that muscle strength was negatively correlated with TGVG, NGV and CRT (P＜0.05). Linear regression analysis showed that 25 (OH) D level was negatively correlated with TGVG, NGV and CRT, and the correlation coefficients were0.53,0.44,046 (P＜0.05), while was positively correlated to the muscle strength, and the correlation coefficients were 0.54 (P＜0.05). Conclusion The serum 25 (OH) D, fall risk and muscle strength are closely correlated with vitamin D deficiency in elderly osteoporosis, so clinical treatment should pay high attention to this point.