Objective To investigate the effect of adenosine on pulmonary injury after extracorporeal circulation. Methods Twelve mongrel dogs were randomly divided into two groups, the test group and control group. The model of extracorporeal circulation was established. In the test group and control group, adenosine(50μg/kg*min) and normal saline were infused before extracorporeal circulation respectively. Hemodynamics, right cardiac function and arterial blood gas were assessed. Lung water and malondialdehyde content were assessed. Histological evaluation was also made. Results　There were no differences between the two groups with respect to heart rate, mean systemic artery pressure, left atrial pressure, and central venous pressure. In the test group, pulmonary vascular resistance was lower and right cardiac function improved remarkably; arterial oxygen pressure (PaO2) was also higher, less lung water was observed and the malondialdehyde content in the pulmonary tissue was lower (P＜0.05,P＜0.01). Histological evaluation of the test group revealed normal pulmonary architecture without abundant intra-alveolar neutrophils. Conclusion Adenosine can attenuate ischemia-reperfusion lung injury and right cardiac insufficiency caused by extracorporeal circulation. At a proper dose, there was no significant effect on systemic hemodynamics.