Objective To explore the correlation of frailty and cognitive function with fear of falling in the elderly inpatients with type 2 diabetes mellitus (T2DM). Methods A total of 199 elderly T2DM patients in the Department of Endocrinology and Geriatrics of First Affiliated Hospital of Dalian Medical University were selected for the study. A self-designed general data questionnaire, the FRAIL screening questionnaire, the modified fall efficacy scale (MFES) and the mini-mental state examination(MMSE)were used for investigation. SPSS statistics 22.0 was used for data analysis, descriptive analysis for general data, and Pearson analysis for correlation analysis. Results The score of modified fall efficacy scale (MFES) was (7.37±1.39)points, and the incidence of fear of falling was 64.32% (128/199). The mini-mental state examination (MMSE) score was (22.71±5.10)points, and the overall incidence of cognitive impairment (mild, moderate and severe) was 72.86% (145/199). FRAIL score was (2.23±0.11) points, and the incidence of frail was 36.18% (72/199). Pearson correlation analysis showed that fear of falling had significant positive correlation with frailty (r=0.570, P<0.01), and significant negative correlation with cognitive function (r=-0.706, P<0.01). Conclusion The incidence of fear of falling, cognitive impairment and frailty was higher in the elderly T2DM patients, and there is a significant correlation between fear of falling and cognitive function and frailty, suggesting that clinical staff should strengthen the early screening of frailty and cognitive function in T2DM patients to provide theoretical basis for reducing fear of falling.