Abstract： Objective To explore the clinical characteristics of patients during recovery period in low flow and circulation closed pattern anesthesia by ZEUS with isoflurane.Methods During elective gynecologic surgery,35 ASA Ⅰ or Ⅱ patients were anesthetized with isoflurane under general anesthesia with tracheal intubation.The ventilation was used with the closed circuit breathing mode (Autocontrol) of ZEUS anesthesia machine.The time of inhale drug,exhale drug and eyes-opend,consumption of drug and complication were recorded during the process.The values of NT stage (NTS),NT index (NTI),the final endexpiratory concentration of isoflurane (EXP),MAC and hemodynamic parameters were recorded during the time of isoflurane stopping inhale,recovery of spontaneous respiration,eyes opening.Results The values of NTI (50±7,74±12,86±10,t =-9.382,t =-16.682,P ＜ 0.01),the EXP [(0.9±0.0)％,(0.1±0.1)％,0,z =-7.262,z =-7.835],MAC [(1.2±0.1)％,(0.2±0.2)％,0,z =-7.186,z =-7.728,P ＜ 0.01] and hemodynamic parameters (SBP,DBP,MAP,HR) [(108.1±13.4) mm Hg (1 mm Hg =0.133 kPa),(66.3±12.1) mm Hg,(84.3± 12.5) mm Hg,(69.8±12.5) /min and (124.6±17.9) mm Hg,(75.7±14.5) mm Hg,(96.0±14.6) mm Hg,(82.8±15.0)/min and (128.0±16.3) mm Hg,(77.1±15.0) mm Hg,(99.8±15.3) mm Hg,(85.2±18.5) bpm] (t =-4.365,t =-2.951,t =-3.574,t =-3.921; t =-5.554,t =-3.309,t =-4.642,t =-4.085,P ＜0.01) during the time of recovery of spontaneous respiration and tracheal extubation were statistically significant compared to the time of isoflurane stopping (P＜ 0.01).None of patients experienced intraoperative was awareness.Conclusion Isoflurane can be used for closed circuit breathing mode of ZEUS anesthesia machine,but consciousness recovery need a long time.