Renal puncture can be performed to clarify the diagnosis, guide the treatment or judge the prognosis, and when there is no contraindication to puncture. (1) primary renal disease ① acute nephritis syndrome, kidney function is rapidly deteriorating, suspected acute nephritis, should be punctured as soon as possible; according to the treatment of acute nephritis 2 to 3 months no improvement in the condition should be done kidney puncture. ② primary nephrotic syndrome, treatment first, renal puncture when hormone rule treatment is ineffective for 8 weeks; or puncture first, differentiated treatment according to the type of pathology. (3) asymptomatic hematuria, deformed red blood cell hematuria when the clinical diagnosis is unclear, asymptomatic proteinuria, proteinuria persist >1g/d when the diagnosis is unclear should do renal puncture. (2) Secondary or hereditary renal disease: renal puncture should be performed when clinical suspicion is not confirmed, or when the clinical diagnosis is confirmed but the renal pathological data are important for guiding treatment or determining prognosis. (3) Acute renal failure: puncture should be performed promptly when the cause cannot be determined by clinical and laboratory tests. (4) Transplanted kidney: ① When the cause of apparent renal failure is unclear; ② Severe rejection reaction to decide whether to remove the transplanted kidney; ③ Suspected recurrence of pre-existing renal disease in the transplanted kidney.