Abstract: Objective　To establish the experimental model of pulmonary artery perfusion during cardiopulmonary bypass(CPB) and observe the protective effect of pulmonary artery perfusion with improved low-potassium detran solution(LPD solution) supplemented by glutathione(GSH) on lung injury during cardiopulmonary bypass(CPB). Methods　Twenty rabbits were randomly divided into two groups: control group(no pulmonary artery perfusion during CPB)and perfusion group(pulmonary artery perfusion with improved low-potassium detran solution during CPB). Blood samples were drawn at different time points during cardiopulmonary bypass for tumor necrosis factor-a(TNF-a) and blood gas analysis and calculate oxygenation index；Malondialdehyde(MDA) and wet-to-dry ratio(W/D) of lung at the end of CPB were measured and calculated. Results With the CPB, the oxygenation index of perfusion group was higher than that of control group, however the level of tumor necrosis factor-a(TNF-a) was lower；Lung level of malondialdehyde(MDA) and lung wet-to-dry ratio in perfusion group were lower than those in control group at the end of CPB. Conclusion Pulmonary artery perfusion with improved low-potassium detran solution(LPD solution) supplemented by glutathione(GSH) during cardiopulmonary bypass(CPB) can ameliorate lung function and attenuate lung injury caused by CPB.