Objective To investigate the relationship between the degree of insulin resistance (IR) and skeletal muscle mass in the elderly patients with type 2 diabetes mellitus (T2DM). Methods A total of 83 elderly T2MD patients in Nanjing Hospital Affiliated to Nanjing Medical University from April 2018 to August 2019 were enrolled. They were divided into two groups:the control group without muscle reduction and the study group with muscle reduction. The two groups were compared in the basic data, blood lipid index, blood glucose and insulin resistance index. SPSS statistics 19.0 was used for statistical analysis. Data comparison between two groups was perfomed using χ² test or t test depending on data type. Logistic regression was used to analyze the risk factors of skeletal muscle loss. Results The age of the study group were significantly higher than that of the control group (P<0.05). The body mass index of the study group was significantly lower than that of the control group (P<0.05). The study group had significantly lower homeostasis model assessment-β (HOMA-β) but significantly higher homeostasis model assessment of insulin resistance (HOMA-IR) than the control group (P<0.05). The appendicular skeletal muscle mass index (ASMI) values were positively correlated with HOMA-β (r=0.441, P<0.05) and negatively correlated with HOMA-IR (r=-0.463, P<0.05). Logistic regression analysis showed that age and IR were independent risk factors of skeletal muscle loss in the T2DM patients (P<0.05). Conclusion Age, HOMA-β, and HOMA-IR are associated with ASMI in the T2DM patients, and age and IR are independent risk factors of muscle loss in the T2DM patients.