To analyze the therapeutic effects of Ziyin Yishen Decoction on primary IgA nephropathy and its related mechanism.Methods:A total of 112 patients with primary IgA nephropathy were randomly divided into a control group(n＝56)and a study group(n＝56)according random number table.The control group was treated with routine Western medicine,and the study group was treated with the syndrome treatment of modified Ziyin Yishen Decoction.Patients in both groups were treated continuously for 3 months.The drift of interferon-gamma(IFN-γ),interleukin-2(IL-2),tumor necrosis factor-β(TNF-β)and Th2(interleukin-4(IL-4),IL-5,IL-6,IL-10),24-hour urinary protein,serum creatinine(Scr),blood urea nitrogen(BUN),serum IgA level changes,clinical efficacy and adverse reactions were compared between the 2 groups.Results:Compared with the control group,Ziyin Yishen Decoction could significantly increase the clinical effective rate of primary IgA nephropathy,increase the levels of IFN-γ,TNF-β and IL-2 in peripheral blood,and decrease the expression of IL-4,IL-5,IL-6,IL-10 and the levels of 24-hour urinary protein,Scr,BUN and serum IgA level.There was no significant difference in adverse reaction rate between the 2 groups.Conclusion:Ziyin Yishen Decoction combined with Western medicine in the treatment of IgA nephropathy can promote the balance of drifting peripheral blood Th1/Th2 system,thus balance the body's pro-inflammatory and anti-inflammatory system,improve the clinical effects,and does not increase the adverse reactions of patients,so it has high clinical value.