The so-called urine erythrocyte locus is simply a method of observing urine red blood cells for abnormalities. The presence of red blood cells in the urine is called hematuria, but the source of the blood is very significant for the treatment of the underlying disease. The source of hematuria can be divided into two major areas in simple terms. First, renal hematuria; second, non-renal hematuria. While renal hematuria refers to the loss of red blood cells from the kidneys, and the process of loss leads to extrusion and deformation of red blood cells, then the proportion of deformed red blood cells will be increased, while non-renal hematuria does not have this characteristic. Clinically, the morphology of red blood cells is observed with a microscope, and if the percentage of deformed red blood cells reaches 80% or more, it is considered renal hematuria. If the percentage of abnormalities is below 80%, consider that it may be non-renal hematuria. This narrows the scope of diagnosis of hematuria and provides a clinical basis for further determination of the cause of hematuria.