Recently, the Department of Nephrology of Nanshan Hospital successfully treated a patient with a newly named glomerulonephritis-C3 glomerulonephritis, and the patient has been discharged from the hospital. It is reported that the patient, a 22-year-old male, came to Nanshan Hospital with “eyelid swelling for half a year and coughing and sputum for one week” and was admitted to the nephrology department as “nephrotic syndrome”. After admission, it was found that the patient had hypertension, nephrotic syndrome, hematuria, and renal impairment with obvious hypo-C3emia. The patient’s condition was complicated, and the nephrology department promptly performed renal puncture biopsy for the patient. The pathology report showed membranoproliferative glomerulonephritis-like changes with diffuse, globular, thylakoid and capillary loop petal-like C3 deposition in the glomerulus; a large number of T lymphocytes (CD3), B lymphocytes (CD20), plasma cells (CD38), macrophages (CD68) and a small amount of neutrophil infiltration (MPO) in the renal tissue; electron microscopy showed subendothelial and electron-dense material deposition in the thylakoid region; hepatitis B-associated nephritis, hepatitis C-associated nephritis, acute post-streptococcal infection nephritis, lupus nephritis, dense material deposition disease, and idiopathic type I membranoproliferative glomerulonephritis were excluded, and finally a newly named glomerulonephritis-C3 glomerulonephritis was definitively diagnosed. The nephrology department formulated comprehensive treatment measures such as methylprednisolone shock therapy, blood pressure lowering, kidney protection to reduce proteinuria, anticoagulation, etc. The patient’s blood albumin level rebounded significantly, urine protein and blood creatinine decreased significantly, urine volume increased, lower limb edema gradually reduced, and was discharged with stable condition. The patient’s urine output was normal and there was no edema in both lower extremities after more than 1 month of follow-up. C3 glomerulopathy is a group of glomerulopathies first described by Verroust et al. in 1974 and named by Fakhouri et al. in 2010. C3 glomerulopathies include C3 glomerulonephritis, dense material deposition disease (DDD), familial type III membranoproliferative glomerulonephritis (MPGN), complement H factor-related protein 5 (CFHR5) nephropathy, and CFHR5 nephropathy. (CFHR5) nephropathy and type I MPGN with simple complement C3 deposition. There are few reports on C3 glomerulonephritis, and the diagnostic criteria are: (1) positive immunofluorescence for C3 and negative for immunoglobulins (IGG, IGA, IGM) and C1q; (2) electron microscopy for electron-dense material deposition in the subendothelial and/or thylakoid region; and (3) excluding systemic diseases. The pathogenesis is mainly related to abnormal regulation of the complement system due to genetic inheritance or acquired factors, the specific mechanism needs to be further investigated, and no effective treatment is available. The patient presented with hypertension, nephrotic syndrome, hematuria, and renal impairment with marked hypo-C3emia, and the condition was complicated. Through timely renal biopsy to improve the pathological examination to clarify the diagnosis, hormones, antihypertensive, renal protection to reduce proteinuria, anticoagulation and other comprehensive treatment measures, the patient’s condition is in rapid remission, achieving good therapeutic results, we will follow up the patient for a long time. Membranoproliferative glomerulonephritis-like changes (PAS) Diffuse spherical thylakoid zone and capillary loop C3 deposition (immunofluorescence staining) Subendothelial and thylakoid zone electron dense material deposition (electron microscopy) Renal interstitial T (CD3) lymphocyte infiltration (immunohistochemistry)