The coexistence of anti-glomerular basement membrane (GBM) disease, idiopathic membranous nephropathy (IMN), and IgA nephropathy in one patient is a very rare case, which has not yet been reported. Whether the three diseases are correlated and the underlying mechanism remain unknown. Herein, we report a 48-year-old female patient that was admitted because of proteinuria and abnormal renal function, which was diagnosed as anti-GBM disease, idiopathic membranous nephropathy, and IgA nephropathy by renal biopsy. The patient received treatment including high-dose methylprednisolone pulse therapy, plasma exchange, and intravenous infusion of both cyclophosphamide (CTX) and rituximab. In the follow-up, the titer of the anti-GBM antibody gradually decreased, renal function was restored, and urinary protein was reduced, without significant adverse effects.