To explore the possible significance and mechanism of ellagic acid in the treatment of IMN, and look for potential options for the treatment of IMN.Methods SD rats (SPF, 8 weeks) were randomly divided into experimental group, model group and control group, with 8 rats in the experimental group and 8 rats in the model group and 6 rats in the control group. The experimental group and model group were injected with cationic bovine serum albumin (BSA) to construct a rat model of idiopathic membranous nephropathy. After successful modeling, the experimental group was intraperitoneally injected ellagic acid at the rate of 200mg/kg body weight once a day for 4 weeks, and the model group was injected with normal saline of the same volume. Four weeks later, the rats in each group were anesthetized with isoflurane and killed. Blood, urine and kidney samples were collected for further biochemical, pathological and molecular biological analysis. Results The renal function indexes (serum creatinine, urea nitrogen, serum albumin, 24-hour urine protein and blood cholesterol) and the components of renal tubular urine protein (α1-MG, β2-MG, RPB, NAG and NGAL) of rats with idiopathic membranous nephropathy treated with ellagic acid were significantly improved, and the P values were all less than 0.05 compared with model group. Compared with model group, Mst1 mRNA expression of experimental rats decreased (P＜0.05), while Nrf2 mRNA expression increased (P＜0.05).Conclusion Ellagic acid may alleviate oxidative stress in renal tissue through the MST1-NRF2 pathway and thus alleviate renal pathological damage in C-BSA induced IMN