Diabetes mellitus is the primary underlying disease causing end-stage renal disease (ESRD), and diabetic nephropathy has been a hot topic of clinical discussion. However, the pathogenesis of diabetic nephropathy is still unclear, so there are many controversies in the diagnosis and treatment. Since there is a lack of uniform diagnostic criteria for diabetic nephropathy, it often causes misdiagnosis in clinical practice. Renal biopsy studies have found that a large proportion of patients diagnosed with diabetic nephropathy have been proven not to have diabetic nephropathy. Before making the differential diagnosis, let us review several common concepts of diabetic nephropathy: diabeticnephropathy (DN), diabetic nephropathy (diabetickidneydisease, DKD), and chronic kidney disease (chronickidneydisease, CKD). Diabetic nephropathy (DN): long-term hyperglycemia can involve all structures of the kidney and can have different pathological changes and clinical manifestations, mainly including glomerulosclerosis, small renal arteriosclerosis, renal papillary necrosis, etc.; while DN generally refers to glomerulosclerosis, and the clinical diagnosis is usually based on microalbuminuria as an early diagnosis. Diabetic kidney disease (DKD): first proposed as a clinical diagnosis in 2007 by the Clinical Practice Guidelines for Diabetes and Chronic Kidney Disease developed by the National Kidney Foundation (NKF). DKD should be considered in the presence of any of the following: massive proteinuria; presence of microalbuminuria in combination with diabetic retinopathy or type 1 diabetes mellitus of more than 10 years duration. Chronic kidney disease (CKD): The concept, staging and assessment methods of CKD were formally established in the 2002 K/QODI Clinical Practice Guidelines for Chronic Kidney Disease. Its staging is divided into stages 1-5 according to different levels of GFR, which are clearly defined and staged. From the concept and definition of the three concepts, DN focuses on pathological changes, emphasizing glomerulosclerosis and its accompanying series of manifestations; DKD is a clinical diagnosis, focusing more on proteinuria; and CKD is kidney damage in a broad sense. Due to the different definitions of the three, the prevalence varies widely. Studies have shown that the proportion of American type 2 diabetic patients aged ≥20 years with combined CKD is 40%; while in China, the proportion of type 2 diabetic patients aged ≥30 years with combined CKD is up to 64%. The prevalence of DKD in type 2 diabetic patients in China is about 28.3%, while the prevalence of DN is only 16.7% and that of non-diabetic nephropathy is 36.7%, which is much higher than that of DN. In addition, it was found that the proportion of patients diagnosed with DN who were diagnosed with non-diabetic nephropathy after renal biopsy ranged from 9% to 85%, with an average of 34.8%. Therefore, in the face of patients with diabetes mellitus with CKD, the possibility of non-diabetic nephropathy should be considered in addition to DN.