Abstract: Objective To explore the relationship between renal IgM deposition and clinicopathologic changes in patients with idiopathic membranous nephropathy (IMN).Methods A retrospective analysis was made on the clinical data of 95 patients with IMN confirmed by subcutaneous renal biopsy in the First Affiliated Hospital of Anhui Medical University from December 2015 to June 2017. The position and degree of IgM in glomeruli were detected by direct immunofluorescence, and then the patients were divided into IgM deposition group and IgM negative group. The serum anti-phospholipase A2 receptor antibody was detected by indirect immunofluorescence, and the pathologic staging was made by Ehrenreich-Churg staging criteria. The clinicopathological and laboratory indexes were analyzed and compared between the two groups.Results The levels of serum uric acid in the same sex group, total cholesterol, 24-h urinary protein, urinary FDP and urinary cystatin C in IgM deposition group were significantly higher than those in IgM negative group (P<0.05). The pathological damage in the IgM deposition group was more severe than in the IgM negative group (P<0.05). Blood immune globulin (IgG, IgA, total IgE and IgM), serum albumin, serum creatinine, blood urea nitrogen, triglyceride, high density lipoprotein cholesterol, non-high density lipoprotein cholesterol, very low density lipoprotein cholesterol, low density lipoprotein cholesterol, apolipoprotein A, apolipoprotein B, lipoprotein(a), the urinary protein including total protein, transferrin, retinol binding protein, N-acetyl-β-D-glucosaminidase, albumin, IgG, β2-microglobulin, α1-microglobulin, and serum anti-phospholipase A2 receptor antibody showed no significant difference between the two groups(P>0.05).Conclusions In the IMN patients with IgM deposition, there was higher blood uric acid level, more obvious disorders of blood lipid metabolism, more severe urinary protein, and more risk of secondary renal tubule injury, suggesting that the disease is more serious.