OBJECTIVE： To observe therapeutic efficacy and safety of prednisone acetate combined with leflunomide in the treatment of IgA nephropathy. METHODS： 80 patients with IgA nephropathy were randomly divided into observation group and control group， with 40 cases in each group. Control group was given prednisone acetate 1.0 mg/kg， qd， 6 weeks later， decreasing gradually， decreasing to 0.5 mg/kg in 12th week； observation group was additionally given leflunomide 50 mg， qd， 3 days later decreasing to 20 mg. Both groups were given 3 months of treatment. Clinical efficacy， 24 h urinary protein quantification， Scr and BUN levels were observed in 2 groups after treatment， and ADR were recorded during treatment. RESULTS： Total effective rate of observation group （95.0％） was significantly higher than that of control group （75.0％）， with statistical significance （P＜0.05）. After treatment， 24 h urinary protein quantification， Scr and BUN levels of observation group were significantly lower than those of control group， with statistical significance （P＜0.05）. The incidence of ADR in observation group （0） was significantly lower than in control group （7.5％）， with statistical significance （P＜0.05）. CONCLUSIONS： Prednisone acetate combined with leflunomide has significant effect on IgA nephropathy， and will not increase the occurrence of ADR.