To observe the clinical efficacy of the optimized integration traditional Chinese and western medicine in the treatment of IgA nephropathy and the immune mechanism of improving renal fibrosis.Methods:A total of 40 patients with IgA nephropathy admitted to Shuguang Hospital affiliated to Shanghai University of Traditional Chinese Medicine from June 2016 to June 2018 were selected as subjects.According to the principle of randomized control,they were divided into an observation group(traditional Chinese medicine granules+Losartan)and a control group(traditional Chinese medicine mimicking agent+Losartan),with 20 cases in each group.The observation group was treated by traditional Chinese medicine granules+Losartan,and the control group was treated by traditional Chinese medicine mimicking agent+Losartan.All were treated for 24 weeks,and the 24 hours urinary protein quantitation,urinary microalbumin/creatinine(MA/Cr),serum creatinine(Scr)and glomerular filtration rate(eGFR),interleukin-6(IL-6)and transforming growth factor-β1(TGF-β1)were measured before and after treatment.Results:The total effective rate was 80.0% in the observation group and 35.0% in the control group,and the difference between the 2 groups was statistically significant(P<0.05).Compared with the control group,the 24 hours urinary protein quantitation,MA/Cr,Scr and eGFR in the treatment group were significantly improved(P<0.05).The nutritional status in the observation group was stable,and the related immune mechanism of urinary IL-6 was significantly improved(P<0.05),and the renal fibrosis factor of urinary TGF-β1 was significantly decreased(P<0.05).Conclusion:Compared with the western medicine group,the observation group(integration traditional Chinese and western medicine)has obvious advantages in reducing proteinuria and protecting kidney function.The regulation of IL-6 is an important mechanism for improvement of renal fibrosis in IgA nephropathy by the optimal treatment scheme with integration traditional Chinese and western medicine.