Insulin resistance is an important pathophysiological mechanism of cognitive frailty (CF) in elderly patients with type 2 diabetes mellitus (T2DM), and early identification of its relevant risk factors and implementation of interventions are of great importance for improving their quality of life. Triglyceride-glucose (TyG) index, as a new marker of insulin resistance index, can also increase the risk of CF in elderly T2DM patients. In this article, we reviewed the research progress of insulin resistance in the pathogenesis of CF and its correlation with related risk factors of CF. We also explored the research progress on the correlation between TyG index and CF in order to provide useful references for slowing the progression of CF in patients with T2DM.