Objective: To investigate the diagnostic value of monocyte to high density lipoprotein cholesterol ratio (MHR), serum creatinine(Scr) and microalbuminuria (mAlb) in early renal function impairment in patients with type 2 diabetes mellitus (T2DM). Methods: A total of 50 patients with T2DM admitted to Xinyu City People"s Hospital from October 2024 to December 2025 were selected as the observation group, and 30 healthy subjects during the same period were enrolled as the control group. MHR, Scr, and mAlb were detected and compared between the two groups. Patients in the observation group were divided into early diabetic nephropathy (DN) group (n=28) and simple T2DM group (n=22) based on urine albumin/urine creatinine (UACR). MHR, Scr, and mAlb were compared between the two groups, and receiver operating characteristics (ROC) curves were drawn to analyze the diagnostic value of MHR, Scr, mAlb and their combination on early DN; the relationship between MHR, Scr, and mAlb and the occurrence of early DN was analyzed usingoint-biserial correlation method. Results: Compared with the control group, the MHR, Scr and mAlb of the observation group were higher (P<0.05). Compared with the T2DM group, the MHR, Scr and mAlb of the early DN group were higher (P<0.05). ROC curve analysis showed that the area under the curve (AUC) of early DN in patients with T2DM diagnosed by MHR, Scr, mAlb and the combination of the three was 0.881 (0.785-0.978), 0.727 (0.586-0.869), 0.852 (0.743-0.961), and 0.971 (0.870-0.986), respectively. Point-biserial correlation analysis revealed that MHR, Scr, and mAlb were positively correlated with the occurrence of early DN (P<0.001). Conclusion: MHR, Scr, and mAlb have good efficacy in diagnosing early renal function impairment in T2DM, but the combined diagnosis value is higher.