There are many causes of hematuria, and the common ones are as follows: 1. Urinary system diseases: (1) Inflammation, mainly primary or secondary immunoreactive inflammation, such as primary glomerulonephritis, IgA nephropathy, allergic purpura nephritis, lupus nephritis, hereditary nephritis, thin basement membrane nephropathy, hypertensive nephropathy, etc. (2) Infections, including pyelonephritis, cystitis, urethritis, prostatitis, etc. caused by common bacteria, mycoplasma, chlamydia, viruses, tuberculosis bacteria and other pathogenic microorganisms. (3) Stones, including kidney stones, ureteral stones, bladder stones and urate and oxalate crystals, etc. (4) Tumors, including kidney cancer, bladder cancer and prostate cancer, etc. (5) Vascular disease, renal artery, renal vein, intrarenal microvascular thrombosis or embolism. (6) Hereditary, congenital urological diseases, such as renal cyst, polycystic kidney, renal prolapse, wandering kidney, left renal vein compression (nutcracker phenomenon), various renal ureteral malformations, etc. (7) Urological trauma or instrumentation operation, such as catheterization, cystoscopy and trauma, surgical injury, etc. (2) Systemic diseases: (1) Infectious diseases, such as epidemic hemorrhagic fever, scarlet fever, leptospirosis, sepsis. (2) Hematological diseases, such as thrombocytopenic purpura, aplastic anemia, leukemia and hemophilia, etc. (3) Immune and autoimmune diseases, such as acute rheumatic fever, systemic lupus erythematosus, polyarteritis nodosa, allergic purpura, etc. (4) Cardiovascular diseases, such as vasculitis, congestive heart failure, subacute endocarditis, acute hypertension, etc. (5) Endocrine metabolic diseases, gout kidney, diabetic nephropathy, hyperparathyroidism, etc. (3) Diseases of the organs adjacent to the urinary tract: such as acute or chronic pelvic inflammatory disease, acute appendicitis, prostatitis, inflammation of the colon or rectum, malignant tumors such as cervical cancer, colon cancer and other diseases that invade or stimulate the urinary tract can produce hematuria. 4, damage to the urinary tract by chemicals or drugs: such as damage to the renal tubules by heavy metals such as sulfonamides, indomethacin, mannitol, mercury, lead and chromium; hemorrhagic cystitis caused by cyclophosphamide; anticoagulants such as heparin overdose can also produce hematuria. 5.Functional hematuria: Healthy people who usually exercise little can suddenly increase the amount of exercise can appear athletic hematuria.