Abstract： Objective To observe the therapeutic effect of cilnidipine to treat essential hypertension accompanied with type Ⅱ diabetes mellitus incorporated with kidney disfunction.Methods Thirty-one patients were selected and treated with enalapril(10 mg twice daily, and randomly assigned to a group receiving cilnidipine 5 mg/day～10 mg/day (17 patients) or a group receiving felodipine 5 mg/day ～ 10 mg/day (14 patients).Then analysis was done for the variation of blood serum creatinine and 24-hour urine protein after treated with cilnidipine or felodipine six months and twelve months.Results There was no statistic difference between the two groups in all basehne value and blood pressure and heart rate in treatment course, but 24-hour urine protein after treatment of cilnindipine group significantly lower than the felodipine group(cilnindipine vs.feledipine: 6 months, 650.5 mg± 253.8 mg vs 951.4 mg± 260.9 mg, P ＜ 0.01 ; 12 months, 646.4 mg± 249.8 mg vs 970.6 mg± 188.4 mg, P ＜ 0.01).cilnidipine group showed an increase in serum creatinine levels (baseline vs 6 months, (136.2 ± 30.9)μmol/L vs (142.5 ± 26.0)μmol/L, P ＞ 0.05)after treated six months and decrease to baseline value level in twelve months,but felodipine group showed more stable in serum creatinine levels in six months and an increase in twelve months (baseline vs 12 months, (134.3± 32.3) μmoL/L vs (159.7 ± 33.2) μmol/L, P ＜ 0.05).There was a significant difference of serum creatinine in twelve months between the two group (cilnindipine vs.felodipine, (134.1 ± 35.3)μmol/L vs (159.7 ± 33.2) μmol/L, P ＜ 0.05).Conclusions Cilnidipine results in a great suppression of the increase in proteinuria and is effective in maintaining renal function than felodipine in patients with essential hypertension accompanied with type Ⅱ diabetes mellitus.