Urine is the window of kidney disease, kidney problems manifested outwardly i.e. hematuria, proteinuria. The causes of nephritic hematuria are nothing but the problem of kidney itself and the problem of kidney itself, i.e. primary kidney disease and secondary kidney disease. The causes of hematuria due to secondary renal disease are divided into several categories: 1. Infectious diseases, such as patients with liver disease, hepatitis B patients can appear kidney damage, clinically may also can be manifested as hematuria, of course, can also be manifested as proteinuria. That is to say, infectious diseases are one of the major causes of hematuria; 2, rheumatic diseases, such as female lupus erythematosus or rheumatoid arthritis, these diseases can damage the kidneys, and the manifestation of the outside can be manifested as hematuria; 3, oncological diseases, including lung cancer, gastric cancer, these patients with solid tumors can be tumors affecting the kidneys and hematuria; 4, environmental pollution, food pollution, heavy metal pollution, which can be manifested as hematuria; 4, environmental pollution, food pollution, heavy metal pollution, can be manifested as hematuria. Environmental pollution, food pollution, heavy metal pollution can cause kidney damage, manifested as hematuria or proteinuria; 5, including hereditary kidney disease can also cause kidney damage and manifested as hematuria. The harm should follow the cause of the disease, and different causes of the harm is not the same degree of differentiation.