Ｏｂｊｅｃｔｉｖｅ　To evaluate the effect of lung recruitment maneuvers(LRM) on arterial oxygenation and dynamic compliance in lungs on un-operated side.　Methods　Forty patients, of ASA physical status Ⅱ, scheduled for selective thoracoscope-assisted pulmonary resection, were randomly divided in to 2 groups(n=20): Control group (group C) and LRM group (group L). After induction of anesthesia, the patients were tracheally intubated and mechanically ventilated. After correct positioning was confirmed by fiberoptic bronchoscopy, one lung ventilation(OLV) was performed instead. OLV was performed routinely in group C. In group L, the same ventilator pattern was set as group C, do LRM once after 20 min of OLV. Both groups are applied LRM before closure of thorax. Vital signs and artery blood samples were recorded at baseline(T0), 20 min after OLV(T1), 15 min(T2), 30 min(T3), 45 min(T4) after LRM respectively, and the end of OLV(T5). Dynamic compliance(Cdyn) was calculated.　Results　Compared with group C, the PaO2 was significantly higher at T2[(150±11) mmHg vs (204±21) mmHg，1 mmHg=0.133 kPa], T3[(154±12) mmHg vs (176±14) mmHg], T5[(442±20) mmHg vs (473±15) mmHg], Cdyn is better at T2 [(21±3) ml/cmH2O vs (25±3) ml/cmH2O，1 cmH2O=0.098 kPa] and T5[(26±3) ml/cmH2O vs (31±5) ml/cmH2O] in group L.　Conclusions　LRM can improve arterial oxygenation and Cdyn in lungs on no operated side. The duration of one LRM is about 30 min, the improvement of PaO2 is distinct around 15 min after LRM.