Objective. The main objective is to study the effect of diabetic nephropathy on pulmonary function and clinical outcomes. Methods. The method is to retrospectively analyze patients with diabetic nephropathy (DN) in our hospital from April 2018 to March 2022 as study subjects. The differences in baseline data, serum indicators, renal function indicators, and pulmonary function of patients at different clinical stages were analyzed and then explored. Finally, logistic regression was used to analyze the risk factors affecting patients’ clinical outcomes and to evaluate the diagnostic effects. Results. Baseline information (age, disease duration, BMI, and systolic and diastolic blood pressure), serum indicators (HbA1c, FBG, 2hPG, TG, TC, and LDLC), renal function indicators (CysC, BUN, and Scr), and pulmonary function (TLC, VC, FEV1, FEV1/FVC, MVV, MEF25, MEF50 MEF75, DLCO, and DLCO/VA) were significantly different
P
<
0.01
; multiple logistic regression analysis showed that SBP, HbA1c, FBG, 2hPG, BUN, Scr, TLC, VC, FEV1/FVC, MVV, DLCO, and DLCO/VA were all key factors in the development of clinical outcomes in DN
P
<
0.05
. ROC analysis showed that all of these important factors had an AUC greater than 0.75 for the diagnosis of DN with high sensitivity and specificity. Conclusion. Serum and renal function indices of DN patients gradually increased with stage, accompanied by a decrease in pulmonary ventilation, and diffusion function; SBP, HbA1c, FBG, 2hPG, BUN, Scr, TLC, VC, FEV1/FVC, MVV, DLCO, and DLCO/VA were all key factors affecting the clinical outcome of DN; controlling blood glucose, lipids, improving pulmonary ventilation, and diffusion function can better prevent the occurrence and worsening of DN.