Left kidney pain can be seen in a variety of diseases: i. such as when the left side of the back is sprained. ii. Gynecological diseases on the left side, such as ovarian cysts on the left side. Third, urinary tract stones, such as left ureteral and renal stones, can be accompanied by hematuria, and the pain is paroxysmal and can be slightly relieved when bending and flexing the knee position. The size of the stone can be clarified by urological ultrasound, and if necessary, extracorporeal shock wave lithotripsy or surgical stone extraction can be performed to relieve the pain. Fourth, urinary tract infection, such as pyelonephritis, can be performed in the middle urine microbial culture, blood routine, urinary routine and other tests to clarify the diagnosis. If necessary, antibiotic treatment can be applied for at least two weeks, the infection can be controlled and the pain can be relieved.