Objective Lung injury occurred during cardiopulmonary bypass as a result of both ischemic-reperfusion injury and systemic inflammatory response is critical for patients' recovery. This study was designed to establish a convenient and appropriate mode for pulmonary artery perfusion and evaluate its effects on the cardiopulmonary bypass-induced lung injury.Methods Fourteen healthy mongrel dogs were randomly assigned to a control group and a perfusion group, which were designed to simulate clinical cardiopulmonary bypass-induced lung injury. Pulmonary arteries were perfused with modified low-potassium dextran solution immediately after the initiation of pulmonary ischemia and before reperfusion, with a pressure of 15 to 20 mm Hg for the perfusion group. Pulmonary arteries of animals in the control group were not perfused. After pulmonary reperfusion, changes in the pulmonary function were evaluated. Results After pulmonary reperfusion, deterioration in the pulmonary function with various severity was identified in both groups. Pulmonary injury in the control group decreased significantly as manifested by a substantial elevation in PVR [with a change of ( 76 ± 7 ) %], decreased compliance [with a change of (30 ±4) %] and decreased oxygenation index [with a change of (45 ±5 ) %]. In contrast, the injury in perfusion group, as compared with that in the control group, was relatively moderate, with a lower PVR [with a change of ( 28 ± 3 ) %, P ＜0.01 )] ,a higher compliance [with a change of ( 12 ± 2 ) %, P ＜ 0. 01] and a better oxygenation index [with a change of (19 ± 2 )%, P ＜ 0.01]. Conclusion The pulmonary perfusion mode used in this experiment could relieve the cardiopulmonary bypass-induced lung injury and preserve pulmonary function effectively. It was expected that this perfusion mode could be used in the cardiosurgery practice expediently, without interfering with the scheduled operation proceeding obviously.