Ｏｂｊｅｃｔｉｖｅ　To determine the dose-response relationship of sufentanil combined with midazolam for high intensity focused ultrasoun(HIFU) treatment of uterine adenomyosis and myoma.　Methods　Thirty two patients have uterine adenomyosis and 30 patients have uterine myoma, ASA classⅠ,Ⅱ, were enrolled. The patients were injected 30 μg/kg midazolam for sedation. Sufentanil was injected intravenously 5 min before the onset of operation. In addition, the sequential method was used in this study. The first dose of sufentanil was 0.10 μg/kg, set geometric series r=1.4 to calculate five step doses, the doses of sufentanil in the next patient was increased or decreased by a step dose according to the analgesia effect of the previous patient. Probit analysis was applied to calculated the ED50(95%CI) and 95% effective dose(ED95)(95%CI) of sufentanil.　Results　The ED50(95%CI) of sufentanil for uterine adenomyosis is 0.18(0.08-0.26) μg/kg. ED95 (95%CI) of sufentanil for uterine adenomyosis is 0.35(0.26-1.30）μg/kg. The ED50(95%CI) of sufentanil for uterine myoma is 0.13(0.04-0.20) μg/kg. The ED95(95%CI) of sufentanil for uterine myoma is 0.34(0.22-1.20) μg/kg.　Conclusions　Combined with midazolam 30 μg/kg, sufentanil has different ED50 and ED95 for uterine adenomyosis and myoma.