Objective:To observe the clinical efficacy of “Chen’s No.9 Formula for kidney diseases” in the treatment of idiopathic membranous nephropathy. Methods60 patients with idiopathic membranous nephropathy were randomly divided into the treatment group and control group,30 cases in each group. The control group was treated with glucocorticoid plus cyclophosphamide and the treatment group was treated with“Chen’s No.9 Formula for kidney diseases”,with a course of 12 months. The clinical efficacy and the medication safety were observed. The changes on 24 h urine protein quantity,plasma albumin(Alb)and serum creatinine(Scr)were compared.  Results:①The total remission rates were 76.7% in the treatment group and 59.3% in the control group. The clinical efficacy of the treatment group was obviously better than that of the control group (P<0.05). ②In both groups,there were statistically significant differences on the levels of 24 h urine protein quantity and Alb between treatment before and after (P<0.05),while there was no statistically significant difference on the Scr level between treatment before and after(P>0.05). After treatment,the level of 24 h urine protein quantity in the treatment group was obviously lower than that in the control group (P<0.05),while the Alb level in the treatment group was obviously higher than that in the control group (P<0.05). ③During the trial,there was statistically significant difference on the incidence rate of adverse reactions between the two groups,the incidence rate of adverse reactions in the treatment group was obviously lower than that in the control group(P<0.05).  Conclusion:“Chen’s No.9 Formula for kidney diseases” shows satisfactory efficacy in the treatment of idiopathic membranous nephropathy with fewer adverse reactions,especially for the patients who are not sensitive to routine western medicine.