The main causes of occult blood in urine in children are kidney infections, stones and systemic diseases. Each child’s individual situation is different, it is recommended to further improve the examination in regular hospitals to provide the basis for doctors to formulate treatment plans. 1. Kidney infection: children with acute pyelonephritis and glomerulonephritis will have occult blood in urine. 2. Stones: children suffering from ureteral stones, renal pelvic stones, etc. will have occult blood in urine. 3. Systemic diseases: when children suffer from thrombocytopenic purpura and other diseases, it will lead to hematuria and abnormal occult blood in urine. There may be other reasons for children to have occult blood in urine, which need timely medical treatment to avoid delaying the best treatment time.