Objective To investigate the relationship between skeletal muscle mass and vitamin D level in the elderly male inpatients. Methods A total of 152 elderly male patients were collected, who were admitted to the Geriatric Ward of Xinhua Hospital Affiliated to Shanghai Jiaotong University Medical College from January 2018 to December 2019. General data, including height, body mass and age, were collected. Body mass index (BMI) was calculated. Appendicular skeletal muscle mass (ASM) was measured via bioimpedance analysis (BIA). Appendicular skeletal muscle index(ASMI) was calculated. Serum 25-hydroxy vitamin D [25 (OH) D]was measured. SPSS 25.0 was used for data analysis. χ² test was used for data comparison.Results The average of serum 25 hydroxyvitamin D was (45.2 ± 21.4) nmol / L with 18 cases (11.8%) in the severely deficient group, 80 cases (52.6%) in the deficient group, 41 cases (27.0%) in the insufficient group and 13 cases (8.6%) in the sufficient group. The muscle mass decreased in 90 cases (59.2%) and was normal in 62 cases (40.8%). The appendicular skeletal muscle mass index of the four groups were 6.3 (5.9,6.9), 6.1 (6.1,7.4), 6.9 (6.4,7.4), and 7.6 (7.0,7.8) respectively, the difference being statistically significant (H=14.189; P=0.003), and the differences between the sufficient group and the other 3 groups being statistically significant (P=0.002,0.008). Serum 25(OH)D (OR=0.976,95%CI 0.958-0.994; P=0.009) was positively correlated with ASMI (r=0.168, P=0.040) and was an independent risk factor of ASMI. Further analysis showed that it had no correlation with the muscle mass of the upper limb (r=- 0.014, P=0.863), but was positively correlated with the muscle mass of the lower limbs (r=0.191, P=0.020). Conclusion The skeletal muscle mass is related to nutritional status of vitamin D in the elderly males, and the skeletal muscle mass of both lower limbs is more affected by vitamin D levels.