Objective To investigate the associations of the thyroid feedback quantile-based index （TFQI）， the thyroid-stimulating hormone index （TSHI）， the thyrotropin resistance index （TT4RI）， and the free triiodothyronine/free thyroxine （FT₃/FT₄） ratio with diabetic peripheral neuropathy （DPN） in patients with type 2 diabetes mellitus （T2DM）. Methods A total of 100 patients with T2DM who were admitted to the hospital from May 2022 to May 2025 were enrolled in this study. Based on the presence or absence of DPN， these patients were divided into the DPN group （n = 43） and the non-DPN group （n = 57）. Clinical data were collected， and thyroid hormone sensitivity indices were calculated. The influencing factors for DPN in T2DM were identified through univariate and multivariate logistic regression analyses. The relationship between thyroid hormone sensitivity indices and DPN was explored via Spearman correlation analysis. The predictive efficacy of these indices for DPN in T2DM was evaluated by using the receiver operating characteristic （ROC） curve. Results In comparison with the non-DPN group， the DPN group exhibited significantly lower levels of FT₃， TFQI， TSHI， TT4RI， FT₃/FT₄， motor conduction velocity （MCV）， and sensory conduction velocity （SCV）. Moreover， patients in the DPN group were older （P < 0.05）. Multivariate logistic regression analysis indicated that TFQI （OR = 0.491， 95%CI： 0.260 - 0.926）， TSHI （OR = 0.594， 95%CI： 0.387 - 0.911）， TT4RI （OR = 0.418， 95%CI： 0.183 - 0.954）， and FT₃/FT₄ （OR = 0.540， 95%CI： 0.352 - 0.827） were independent factors influencing the occurrence of DPN in T2DM （P < 0.05）. Spearman correlation analysis demonstrated that TFQI， TSHI， TT4RI， and FT₃/FT₄ were significantly negatively correlated with DPN （r = -0.563， -0.501， -0.541， -0.292， P < 0.05）. ROC curve analysis disclosed that the area under the curve （AUC）， specificity， and sensitivity of the combination of thyroid hormone sensitivity indices for predicting DPN in patients with T2DM were 0.918， 90.70%， and 93.00%， respectively. The AUC and sensitivity were significantly higher than those of TFQI， TSHI， TT4RI， or FT₃/FT₄ when used alone （P < 0.05）. Conclusions In patients with T2DM， a decreased sensitivity to thyroid hormone indices is closely related to the occurrence of DPN， and these indices are independent influencing factors for DPN. The combined detection of these indices can improve the predictive efficacy for DPN.