As an important complication of diabetic mellitus, diabetic nephropathy (DN) has been the main cause of end-stage renal disease. It is of great importance to diagnose DN early, and to identify the risk factors of disease progression in order to carry out in-time and effective therapies. Previous literatures have reported the role of several clinical factors in the diagnosis and progression of DN, including age, longer diabetes duration, diabetic retinopathy, higher level of hypertension and HbA1c, and so on. However, the significance of these clinical factors is still controversial and limited. This review aimed to evaluate the values and limitations of these factors in diagnosing and predicting the renal outcome of DN.