Objective To evaluate the median effective dose of alfentanil combined with propofol for inhibiting double lumen bronchial intubation response. Methods Patients undergoing double ⁃lumen bronchial intubation were assigned to male group and female group. All patients were given propofol 2.0 mg/kg combined with alfentanil intravenous anesthesia. Dixon sequential method was used to observe the effect of medication on patients. Probit regression analysis was used to calculate median effective dose（ED50）and 95% confidence interval（95% effective dose，ED95）of alfentanil for inhibition of response to dual⁃lumen bronchial intubation. Results The ED50 and 95% confidence interval of male group were 77.9（34.4 ~ 92.9）μg/kg. The ED50 and 95% confidence interval were 66.7（60.5 ~ 76.0）μg/kg in female group，and the difference was statistically significant（P < 0.05）. Conclusion When combined with propofol 2 mg/kg ，the ED50 of alfentanil inhibiting double⁃lumen bronchial intubation response was 77.9 μg/kg and 66.7 μg/kg in male and female groups，and there was gender difference in the ED50 of alfentanil inhibiting double⁃lumen bronchial intubation response.